QIf I have multiple cards with an "At the start of your end phase" ability triggering, in what order do I resolve them?

AYou can resolve them in any order. When you proceed to your end phase, all "At the start of your end phase" abilities are triggered and become pending. Then, you can choose the order in which you resolve the pending abilities.

QIf my maximum number of play points is 1, do I still recover 2 play points with Barrage Brawler's On Evolve ability?

ANo. You will only recover 1 play point because your remaining play points cannot exceed your maximum play points.