Grin, I'll give it a shot.  I'm well used to intro'ing cats to established
cat homes and have some experience with adding a dog (currently doing that
just now).

First I'll ask for a little more info.  (yes, with puppies it's normally
fairly easy especially if the cat is a year or more old at the time).  That
same method (depending on what you did) will be only partly applicable.

The personality of the dog is the most important part.  Some 'breeds' have
tendancies but their own personality can over-mask that so personality is
the primary thing.   Secondary is 'breed' but easier to explain, so if you
can make a rough 'guess' on breed mix (at least maybe be able to say 'she
looks mostly kinda labrador like') go to google and check what you see.  I
think it was www.doginfo.com that had a rundown on which types were a bit
more apt to be adaptable.  It's good to at least look it up and keep
whatever you find in the back of your mind.

For sake of arguement lets say you look at some pictures and with her owner
come up with the idea that she's mostly seeming a mixed collie with perhaps
a bit of shepard?  Look up collies and shepards.  See if they both seem 'cat
or small dog friendly' (no, I didnt look up those specifically, just making
a sample).  If however the mix seems to lead that direction, it means it may
go a little easier.  Do NOT 'assume' safety however!  Personality is more
important and the breed info is just an average trend.  Same thing if you
look it up and all mixes she 'seems' to match sorta, are described as 'cat
killers'.  Her age and personality may make her quite cat friendly despite
that, but exercise more caution.

Ok, now for some specifics based on what you've listed.  Your cats are at
least, 'dog tolerant'.  They have also been 'exposed' to dogs.  (How many
cats BTW and rough ages?).  The fact that the Boston Terrier is listed as
normally getting along well with non-canine other pets is a good thing and
apparently 'Boku's' personality follows the average.

How your cats reacted initially to Boku is critical.  Did they run away
immediately or did they look him over while you held him to see the
reaction?  How did you intro them then?

I do _not_ advise trying to hold an 80 lb dog and intro'ing the cats BTW.
If your cats have any brains, they will scatter the second them see her.

Forcing an introduction this time, is not (IMHO) a good idea.  It should be
allowed to happen naturally, at the pace of the cats.  Your cats will
probably be scared silly of Nala at first, if only due to shear size!  Now,
if Nala walks in first time, and the cats scatter that's normal.  If she
tries to chase them down, you might want to rethink this living arrangement.
If however she just looks interested and 'walks' around sniffing in corners
and places the cats perch on (getting their scent), then you probably have a
dog that can adapt.  *probably*.

Specifics on what to do:  Clear down any breakables/fragile items from the
room she will be in first.  Close all exit doors firmly.  Fragile this time
is based on what an 80 lb dog can do to your coffee table <grin>.  REMOVE
the cats from the room before closing the doors.

Bring Nala in.  If she goes 'ape' at the scent and starts trying to get past
the door where the cats are, especially barking like crazy, take her away.
Get more expert help than I can give but at this stage, I would refuse to
have the dog.

If Nala goes a bit ape but not hugely, finds the door the cats are behind,
then 'marks' on the door, you have a different problem (possibly the first
one too).  Alpha leadership.  If one of your cats insists they are 'alpha'
to the dog, there's gonna be a challange fight.  I personally would not take
the dog with this action either, due to the size issue.  Someone's gonna get
hurt and it's hard to say who.  If you got a mega scrapper cat, you may have
a blind dog on your hands.  Nor will it be safe for you to try to separate
them in a battle.

Do setup a 'cat safe' room.  Even if your cats normally wander the whole
house, you need a room where they can 'hide' that Nala either cant get in
(small pet door she cant pass) or stuff in there way to heavy for her to
move that the cats can fit behind or under.  Example: I have a low bed.  My
cat can easily get under it, but my dog can not fit more than about 6 inches
of his head in.  It's a king size bed.  I also have several dressers my cat
can jump up on with ease, but the dog can not.  In addition to all that, the
inner master bathroom has a small (cat sized) 'door' that the dog can not
fit through.  I also have several spots in just about every room that are
'like that' in such a way that my cat knows she has an egress anytime to 1
or more spots where my dog simply can not 'fit'.

Do allow the cats to drive the meeting time and method.

I am sure others will have more to add!

Ok my 'DO NOT' list might be handy as well?  I doubt you would do any of
these but I have seen folks do some unusual things due to lack of
experience.

Do NOT try to put the cats in a carrier and bring them by for the dog to
sniff.  You will terrify the cat(cats) and unless you got a really *strong*
carrier, Nala if of the wrong nature will bust through and have lunch.  Most
cat carriers have doors strong enough for a cat, but not for an 80 lb dog.

Do not attempt to force the meeting.  This can not only lead to false
'safety feelings' on your part if it seems 'ok' but can be very dangerous to
the cats.  This is the most frustrating step by the way as it can take
*weeks* or even 2 months before the cats decided to be calm about being in
the same room with the dog.  (this is radically different from the puppy
with cats).

Do not attempt to get them to 'play together' or 'sleep together'.  Let them
determine if they want to do that (if ever).  Nala was not raised with cats
as a puppy and from what my experience shows, this normally only happens if
both were raised from puppy/kittenhood with the 'other furry faced type'.

Now the situational list.  If Nala is crate trained, it is not a bad idea to
bring her in (with her normal crate and all her normal bedding, not too
recently washed!) and gently let her in her crate, then see if you can coax
the cats to come out.  Perhaps a can opener might be a way that works
<grin>.  As soon as the cats see Nala can *not* get out, you can get a feel
for the interaction by watching Nala.  If she snarling and growling, and eye
tracking the cats, not a good sign.  Do NOT put her in a crate this way if
she isnt long term crate trained.  You'll scare and upset her.  If Nala
tracks them with her eyes and just whines just a little, perhaps with a
slight tail wag, she may be very cat friendly and just not exposed much.
Caution on intro still needed, but a really good sign would be to have the
cats carefully approach the 'cage/den' and gently sniff at it and Nala to
take this well without even standing up.

If Nala is babygate trained and *reliable* at it, you setup babygates here
and there.  The cats will learn right away that little 2ft or so barrier
they can easily leap, is a way to get away if Nala wants to play and they do
not.  Obviously an 80 lb dog can eat that little gate if she wants to
<grin>.

That Nala has a sweet and responsive nature, is a good sign but not always
indicative of how they wil handle cats.  It can be, but check carefully.

Details:  My cat and my dog are both rescue pets from the local facility.
On a 1 (hates the other type of fur face) to 10 (oh, can we play or sleep
together please?  Cats and dogs, living in sin), both are 10's.  Both were
raised as far as any can tell, from kitten/puppy hood with the other sort.
The dog is crate trained (we thought that cruel til we learned more and how
to use it as a 'den') as well as extremely reliably baby-gate trained.  The
dog was here, and in his 'den' when we brought in the cat, and let her loose
in the master bedroom.  Door closed.  Later that night when the dog was in
bed for the night, we opened the door and she investigated the house.
(finding a prefered safe-room, just as neat as the bedroom to her mind).
Within a week she was sahaying along when the dog was calmly resting.  It's
been about 12 days now and for the past 2, at 'afternoon nap time' she takes
the top of the sofa, he takes the bottom, and she and he clean their own fur
in tandem and sniff gently at one another.  Cat is alpha, dog is not <grin>.

Nala arrived yesterday with my friend and so far it has been very
uneventful. Nala is extremely mellow, has wonky hips, can't move very fast,
can't see well, is partially deaf,  doesn't guard her food, loves people and
has shown only mild interest in the cats.  She is very responsive to voice
commands (when she can hear you!).  She has already made tentative friends
with Hailey, who is the dumb blonde type (no offence meant being sorta blond
meself!)  She is very distractable--you clap your hands and she'll come
gallumphing towards you.  I do think this will work--of course I'll be
keeping a gimlet on on her.  She is a real sweetheart and looks very
formidable.

Except for Hailey, the rest of my crew is not so impressed.  Gollum and
Linden are big-eyed and puffed up and keeping out of the way, Clover is
playing hard to get and Sophie, tramp that she is, has used some frightfully
foul language to voice her strident opinions.  We are not pushing any
introductions--Hailey sort of introduced himself, Nala sniffed noses with
him and wagged her tail gently.  One of the cats (probably Sophie) gave her
a swat--Nala merely blinked in surprise.  Hopefully things continue this
way!

Thanks for all the good suggestions and comments!

Bonnie

PS  By the way, she is part pit-bull (actually American Staff Terrier) and
is totally dog and people friendly.  Evidently she was used initially as a
breeder and then abandoned--my friend adopted her when she was two or three.