#1 seems to be more an issue with the game difficulty and not the one roll. Or not necessarily even the difficulty, as apparently there are a great many people that can exploit the ruleset and make every fight rather a breeze. I daresay Larian simply does a bad job at explaining things to the player, how to deal with issues that arise through combat.
#2 is certainly a debatable thing. I am not that far, but I suppose if the captured Druid is seen walking free, the whole camp would indeed turn hostile? But there could be bugs with that I suppose. You could argue though that fighting noises in a cave or building with explosions, fire and the general clang and screaming would alert quite the neighbourhood.
It sure is inconsistent, as you explained in your example, but I suppose this is just a way how Larian balances engagements.
