I wish that I had the right words to say, but it sounds as though you may have taken in a few too many Cats.
I dont of course mean that as a negative comment, ut it sounds as tough a few of your Older Cats are stressed out.

I hope that they can get used to each other.
My Princess has been pooing and peeing, and thats with the lowest Found Cat Hotel population in years.

We are praying that you have Happy Cats and Dog and a Clean House too.