1.) Not that I'm aware of. Just make sure none conflict with each other. 2.) You need 2000 gold I think. Or is it 5000? Might be 10,000. I don't remember. To buy it, go to the Market district and there is an office there. Not exactly specific but it's been months since I've played. 3.) I think the best light armor is the Dark Brotherhood armor. Best 1 handed sword is a Daedric short sword, I think. Best shield is glass shield if I recall. Daedric shields are heavy. Daedric bow is best (actually, enchanted ones are best) and daedric arrows but they weigh a lot. I just used silver arrows.