anyone know how many American plans to hire this year and next?

No idea but I know a ton of dudes who have recently got the video interview request. I'll try and write one of my buddies who just started training. They may have told him.

700-800 per year for the next several years and probably much more after that.

They will try and hire 750 this year. Going to try and run a class almost every two weeks.

Flow or not has nothing to do with seniority or picking equipment/base
Most psa/Piedmont flows are going to us air side for now. Envoy to only LAA
For picking Oldest guy in the room picks first. Then next oldest. It's that simple

Not totally true. We have a Envoy guy that wanted the LUS and was awarded it. They basically asked each newhire what side they wanted and said they'd try to accommodate. I do believe the Flows actually get first choice on what side they want and what's left is divided amongst the rest of the newhires.
Of course recalls get what they can hold.

What happens if say 200 furloughed pilots decide they want to come back by that May deadline. Does hiring come to a screeching halt to get them all in ASAP? Or do they slowly come back with off the street hires and flows over time?

The music stops for OTS hires and flow-throughs while they are brought back.

Or they just bring all the applicants into cowboy stadium and say the last 200 standing get job offers. Go!

I'll bring the popcorn.