Since the colors of the promotions for Minutemen and Helicopters in the default games are reversed (ground unit has air color and air has ground) and the ground unit cannot use roads while the flying one can, all signs seem to point to it being a straight-up bug and not "working as intended". As a result, I decided to included a switch to the promotions in the
unofficial patch mod.
About Hiawatha, I agree he's a very interesting leader. I like playing the Iroqois, and have gone through several games as that civ. Despite this, when stacked up against the powerful civs (like Greece, China or Babylon) I do feel the buffs are warranted to bring them up to that level. Remember the Longhouse is also a trade-off from the Workshop, not an addition, so cities have lower building production (compared to other civs) in regions where there's not many forests around. I feel that reducing the situational nature of the building results in smoother gameplay for the civ.
Something else to remember is the forest trade bonus requires the Roads tech, and cultural borders, both of which can be key limitations. In addition, the "road movement" part of it isn't too great. If you move from a forest tile to a hill tile with a road on it, your unit consumes all its movement points. Same thing with crossing rivers even with bridge-building, and some other situations. In the games I've played, the road movement bonus has rarely been useful other than to let workers improve forest tiles slightly sooner a few times.
That said, if you've played a game as them and feel they might be overpowered, I could remove one or both of the Mohawk Warrior buffs.