People do it all the time with cats who have been together for years
and will, all of a sudden, seem to hate each other.  They separate them
as though they are cats who have never met and begin the intro process
all over again.  I said it in the other thread because you are
apparently thinking of returning them.  I would exhaust every
possibility before doing that because you said you love them.
Something is apparently going on or else they are just being normal
kittens, in which case the separation is not going to cure the problem.

Candace

I have to tell you it all sounds like normal kitten behavior--it will pass.
Cats are basically nocturnal hence kittens generally are a lot more active
at night.  All that roughhousing is pretty normal & I would not consider
medication.  Try giving them things to play with that will keep them
occupied.  They like height, no need for expensive cat condos--try boxes
stacked up that they can go in and out of; stacks of books, etc.  Open paper
bags are great treats expecially if there are treats inside.  They love to
bat around corks, toilet paper rolls, etc. Also, they may be scratching each
other because their nails need to be clipped--kind of required with indoor
cats.  You can get nail clippers for cats pretty cheaply or if you have a
friend or a friendly vet, they can do it for you.  A scratching post helps &
you can make that yourself by wrapping sisal rope around something hard--a
piece of wood, thick cardboard, etc.  Hang one up on a door, leave another
on the floor & put some catnip on it (you can get a really cheap catnip
plant at Home Depot & it grows like wildfire!).  Any kind of 'fishing pole'
kind of toy is great for them--even a piece of string with ribbon on the end
hanging off a rod or coat hanger.  They will play with you for hours with
that....

Just keep in mind, they will grow out of this 'terrible two' stage pretty
quickly but in the meantime, try playing with them as much as possible
during the day so they get a little tired by nighttime!

After having an older cat, kittens can be quite a shock to the system. They
naturally are rambunctious. You will need to 'baby proof' for a while. If
you don't want to risk something getting broken, put it where the cats can't
get to it. As others have said, you need to play with them and see if you
can tire them out before you retire for the night. If need be set up the
other bedroom so that you can leave them in there overnight so you can get
some sleep. It's going to take some time for these two to settle down
though. These guys just sound like they are full of energy and bored.