Yeah, spriters like Oblivionmew can work on backsprites as well. But remember, people have different specialties and it's not wise to ask an overworld/trainer spriter to work on other things like tiles or fakemon sprites.
No, and I would know considering I recruited all but one of our spriters. I already scour the thread for good sprites and spriters, and I can tell you which ones are acceptable and which ones aren't. The spriters already our team also can do this very well.
Also, we have a lot of spriters already and we're trying to figure out what to do with them. We don't need more for a while.
You haven't gotten on AIM in a while and I've been busy with other things, so I haven't told you yet. She's a concept designer. She's helping me with things like stats, items and game mechanics. You'll see her work in full force sometime around late spring, because the things that she and I are working on are so time-consuming and complex.