As far as the stragglers i would say do what u want. In my case the ones that grow up on the cheek are growing significantly slower than the rest but i dont care enough to trim em and they dont add anything as far as density is concerned. If you want neat then trim em if its not that big a deal then leave em. Its yours do what u want. In my case they neither harm nor help so i just leave em cause from a couple feet away u cant really tell. Its really preference. But if ur going for a 4-5 in beard do they really matter?