We have developed a routine where they have the run of the bedroom and bathroom during the day but only the bathroom during the night. At that time we let the other 2 cats have access to the bedroom. That way they get to spend time with us and everyone can get familiar with everyone else's scent. I was also worried about how well the kittens were litter box trained. One of them had an accident the first night. I think it was more due to the fact that they were unsure about hopping into and out of bed. Judging from the amount of poop and pee I have scooped out of the box, I would say they are trained. The next big hurdle will be to bring the entire family together. That will probably happen during the holiday weekend.
Outside of that they have been little bundles of joy. They have that bad kitten habit of "Oh boy! It's mom/dad! Let's climb their legs to get to their shoulders!" Not an issue while wearing pants. BIG issue if you're wearing shorts! I was also a little worried that they never seemed to purr. That fear is now gone. They both have strong little motors. The only other issue is that they are still used to suckling on momma's teat. That doesn't work when they try to get milk from my moobs. Ow!