Uuugggh... Nice name...
1. well, to be honest, there is none, but for optimisation's sake, with characters, go for 2000-6000, weapons, 2500-5500(Including hands), props 120-550, etc.
2. Yeah, you can flesh out the enviroment allright, a perfect example of that is a game named Beyond life, just search for it down below.
3.(Should be two but who cares!), Well, your fine with Photoshop to be honest, all you require is a *.DDS plugin of whom nvidia have made(Search via google), saves ton's of time, but you can also use *.Bmp, *.TGA, *.PNG(My fav), and *.Jpeg/Jpg.
4. Uv-map as you always have, just make sure the map size's are perfect for the model.
5. Normal mapping in FPSCreator... Well... To be honest, even with "Coz'z Shaders" there still going to look crap, so in my opinion... No.
Anyways, have fun, but when I say that Fpsc aint too great, I really really am being kind by saying that(It's el-terribel for me).

"Your greatest teacher is your harshest critic"-'Butterfingers'