Yea I take serious issue with the fact that we can not convince Zevlor the leader of a group that charged into the hells (The Hellriders) to fight some goblins so they can get to Baldur's Gate is a bit ridiculous. Also I think your parallel of the situation to real life is your own head canon but that's not the point. I agree the entire handling of the druids feels awkward and overly restrictive for a game that should be open ended.
Just realized that Wyll is suspicious because either he did not get on the nautiloid or I am missing something I hope this was not a continuity error that is pretty embarrassing.
Otherwise yea I agree with what you're saying, the tieflings need more options, the shadow druids need more options and the solutions need to make more sense in the context of the greater story.
Only Zevlor is a Hellrider, his bodyguard and the dude training the kids seem to be the only fighters, many the angsty dude too.
So one Hell rider and 3 fighters