He's not thrilled to have the harness put on him, but he'll tolerate it (he
"bites" me when I put it on or take it off, but not that hard - at least not
until last night when he definitely made his point (pun intended)) - but
that wasn't serious, more just a scratch.

So every evening I put his harness on and tie a long leash to the coffee
table and hook him up.  He really, really likes being out and about with
everyone, so he's happy.  And I'm still able to keep him "quarantined" since
none of the other cats get too close to him, yet they do get to see and
smell him and him them.  Everybody gets treats, skritching, and playing
with* so that they'll, hopefully, start associating good things with each
others' appearance.  There's still a small bit of hissing going on (mostly
Demi and Jessie whenever they look over at him, but Archer will also hiss
occasionally since he doesn't like it when Hunter tries to play with his
tail).  But Hunter doesn't do any hissing at all - he just purrs really
loudly at everyone.

The harness and leash keep him from indulging his instinctual chase response
when any of the other cats run around him, so there aren't any bad
confrontations.  This is very important for Sammy - when he's on the leash
she can observe him "safely" from a distance and I'm hoping she'll get used
to him enough so that she won't panic when he's no longer leashed.

*I'm beginning to think that Hunter may have been hurt or abused in the past
because of his reaction to "stick" toys.  When I try to play with the furry
string on a stick (which has feathers on the end of the string) Hunter will
panic and try to run away.  It sickens me to think that anyone could have
deliberately hurt him in the past, but given the condition he was in when he
found us it wouldn't surprise me.

Anyway, any spare "good integration" purrs you have would be much
appreciated.