First of all, congratulations both on finding the love of your life, and knowing that she came with cats, didn't demand she get rid of them!

Oscar sounds like a real handful. Does he have toys that he can play with to keep himself busy? As for him chewing things, like shoes or a favorite shirt, the only thing to do is put stuff where he cannot get them. You can also try - in the case of shoes, spraying the laces with bitter apple spray - available to pet stores, but first I'd try it on something you don't care about, just in case he actually likes the taste.

An alternative to the spray bottle - which has obviously lost its effectiveness with him - is a soda can, washed out and then with a few pebbles dropped in - tape over the opening and shake, and the noise will be deterrent for some kitties.