RE: How to recover from a tip (wing) stall?
For most models, given enough altitude, you can get out of any stall. Of course some models take a lot longer to get out of some situations than others.
You can set up a model so that you can get it into a spin that you can't recover from or that will take more altitude than you'd reasonably have when flying models. I've seen it done a couple of times (with the messy results). (to do it, you need a small vertical tail, and a fairly high wing loading, and usually a lot of control throw to get into the spin in the first place).
There are also lots of planes that you an set up to do a really deep flat spin where the plane won't come out if you just release the controls, but will come out if you give the right controls in time.
In terms of "types of stalls", it's a matter of one wing or both being stalled and how much. You can also sometimes stall the horizontal tail as well, but that takes work.