Got a question about this and just wanted to update here how those bottom tree perks are unlocked. You only need to purchase the nodes DIRECTLY and NON-CONSECUTIVELY attached. You don't need every single Node on the bottom tree to get those perks, just the ones that have one line connecting the node's side to the perk's side (each bottom tree perk is only connected to 2 nodes). Some people were confused because technically "attached" and "connected" could mean the nodes are all chained together. Y'all seem pretty smart, but just in case I wanted to have the clarification out there.

Similarly regarding PAA generally you're not allowed to give your actions to other players. Every player MUST act before actions refresh. Not at the start of the round. If you're finding certain players are never acting to prioritize other players you probably are getting this rule wrong.

So Players A and B could use 4 actions in a 4 PPA encounter then during the next allied phase they'd have no actions left. They need to wait for Player C (the last party member) to use their 2 actions before all 3 of them get their actions refreshed ((leaving 2 actions to be taken during this Allied Phase split between the 3 players)).

This is stated a few times in the book but the same group who was confused about the connections wording got confused about that.