Yes, AA has 16,000 applications. Delta has well over 10,000 applications. Same with United, but it's the same 16,000 applying to all three companies.
Yes, the majority of AA hires are through the flows. Most off the street hired at AA are military with a splattering of civilian pilots.
All of the AA furloughed pilots have until May 6th to return. I personally know two pilots on furlough who will not accept the recall. The closer we get to May 6th, the less likely the furloughs will come back as they have found other work or their life situation has changed.