The judge at FNM wasn't a hundred percent sure on this, but he ruled in my favor. I'm pretty sure I was right anyway, but I thought I'd check in with the experts here and get their opinions.
If my opponent flashes in Faerie Invaders (or any other creature with flash, I guess) during my attack step, do I get priority between when it enters the battlefield and when blockers are declared, so I'd have an opportunity to tap it down with Downpour before it can block?
If my opponent flashes in Faerie Invaders (or any other creature with flash, I guess) during my attack step, do I get priority between when it enters the battlefield and when blockers are declared, so I'd have an opportunity to tap it down with Downpour before it can block?
Yes.
After any spell or ability resolves, the active player (you in this case) gets priority. The declare attackers step will only end when all players pass priority in succession with the stack empty.
You will be able to play Downpour before the Faerie blocks. The latest the defending player can play the Faerie Invaders and still block with them is during the Declare Attackers step. After the spell resolves, you will receive priority and can play your Downpour. If you pass priority and the defending player plays nothing else, however, the game will move to the Declare Blockers step where the Faeries can block before any player gets priority