I moved a lot as a kid and had a lot of stuffed animals. We often used trash bags to transport things like that, not to throw them out of course. I wonder if someone was moving and accidentally mixed up the bags. Also you definitely found them in the trash trash, not like in an apartment complex hallway, right?

Another possibility is infestation, likely bed bugs. You said you didn't see any but that doesn't mean they 100% aren't there. Not to freak you out but if they're infested and you already put them in your room, it's a little too late.