He'll probably be alright, but keep an eye out on him.

This could be a gateway to more devious criminal behavior.
First it's pick-pocketing, then he may graduate to cat-burglar.
I'd check his room for anything illegal when he's outside playing.

Probably.  Cats have the digestive system of a garbage truck, we used
to have indoor/outdoor cats and they would bring in and eat entire
small animals, bones, fur, teeth, the lot.  But you should watch
carefully and if your cat seems ill whisk him off to the vet pdq.

My cat Tigger loves to eat plastic.  She is obsessed with it.  She is
normally a very well behaved cat and will immediately stop whatever she is
doing if told NO.  But with plastic she will look at me and keep chewing.
Trash cans must either be bagless or behind closed doors.  we must bring in
the groceries one bag at a time and immediately empty them and throw the bag
away in the hidden trash can.  Despite all our attempts I find plastic bag
pieces in her poop all the time.  Doesn't seem to bother her.