Welcome, hope you enjoy Ic2 =D
1. It can put out all of the above. depending on how much power is being generated per reactor tick. so for most of the smaller simple reactors you can just use copper cables.
2.The reactor should be build one block high then the block it sits on removed and replaced with a reactor chamber. that being said. only a 3x3x3 around the reactor itself is affected by outside cooling(water/air). If you built it directly on top of a MFE i think that would count as a solid and you would lose one block of cooling, ( but adding chambers and cables dont count that way IIRC so could just put a cable out of top or bottom and keep the cooling (air))
3.Currently your best bet if running a hot reactor is to put a source water block directly above the reactor 2 or 3 blocks so when it starts to evaporate the water it only gets the flowing water around it. If you are looking for a good water mod to do something along the lines of real containment. You should check into Finite liquid 5.0 (which i just checked he finally released yay) its a bit more cpu intensive (best to make a world and wait 5mins lol) after it loads tho its ok.
http://djoslin.info/finiteliquid.php