You'll need 459 feathers for the trophy if you're going for that. I'm not sure if that's a good amount for where you're at. I wouldn't worry about it too much. As long as you're opening bags and search points you'll get all of them by the end, or at least be close.
The navi thing... You mean where you set the quest as your objective or whatever? I never used that when I played but I think it just puts the objectives for that quest in the corner when you hold R1(?) instead of having the main quest objectives there.