Region lock is most certainly not a thing anymore on PS4. It was in the beginning, though that passed after we announced our region merge. I'd question the time zones to be quite honest. Especially with us having so many international players. It's a great thing of course, but it makes it harder for all of those players to play together as a result of their time zones.
As always, if you ever experience lengthy queues for any reason, I'd stick to the "Any" game mode, and mix your fleets up.