As for the two-handed weapon style, you could give them Favored Power Attack from Complete Warrior.
As an alternative to these fighting styles built as a list of feats, you could just assign abilities in place of feats where no pre-existing feats existed. That would allow from somewhat more unique fighting styles that fighters would not be able to duplicate.
You could also have each style be a sort of generalized Weapon Style feat which allows for the gaining of new abilities based on your BAB or your ranger level. Since a lot of what I said is ideas which contradict each other, I hope that you were able to at least get something out of this which helped.