This is one of the few games where I won't be following guides - from what I've read feathers & flags are on the treasure maps you buy. Even if they're not, I know I'll enjoy running around looking for collectibles. TBH I just wanted to make sure I got the missable achievements.
For the Nozza/Yunder disagreement, I just have the feeling it's an argument about ego on both sides. Especially since there really isn't that much skill involved in getting any of the achievements, and I've got the impression none of you made the videos you posted (but please correct me if I'm wrong).
I guess there would have been a way for all of you to collaborate on one same guide by just communicating a bit and not trying to make it 'your' guide...