Angels will kill most livebearers. They also attacked my dwarf gouramis. They are poorly named, I can't think of a fish which acts less like an angel.A) tetras(small) barbs (small) corydoras, livebearers (common), Plecos (but keep an eye on max sizes), danio's, angels (but may prey on smaller fish)
B) most if not all cichlids are aggressive. but if keeping malawis (very aggresive) keep them in a tank of their own.
new worlds id say a bolivian ram is the most placid closely followed by german blues and apistos
No matter what planting you have, angels can chase other fish biting their fins until there is nothing left of it. I have one passive one which wouldn't even look aggressively at another fish. The aggressive one physically chased dwarf gouramis and guppies into the weeds biting them until there was nothing left of their tail, and though it's not the most densely planted tank, I would say that it depends entirely on the angel you get, they all seem to be different in temperment and personality.most cichlids are aggresive, but their are exceptions, rams are generally quite peacfull as are angels (but you do have to be careful, if your tank is well planted or has lots of hiding places angels will be fine.