I think you can technically recycle probably almost any plastic, perhaps almost any material in general. It's just a question of if the recycling process is affordable and competes in price with just buying the unrecycled version of that plastic. So other plastics besides PET and HDPE I'm sure you can recycle, it's just that the cost is prohibitive.

Technically yes but there has to be the infrastructure to do it. Most cities cannot process them. It's also generally not profitable and does not save much from an emissions standpoint either.