1 yes Bard is a good class... Bard \ Ranger not so much but its doable
2 bullshit i mean yes they don't agree much but they do not come to blows over it... at least not in EA
3 there is no correct way to play a Bard... they are by design a little bit of everything so how ever you want to use them is fine (personally mine tend to be more hack and slash by level 5)
4 no
5 yes its possible to get the rewards apart from helping any of the groups or even killing all of them and you already figured out a Bard makes a great thief but the only way to get Minthara into bed [kind of a reward] is to kill all the druids for her... of course you can kill her after sex and in all honestly will prob have to anyway