I have a ticket (booked via AA) that has a domestic AA flight to Logan, then a 1:40 minute transit at Logan to Qatar going (biz class) to Doha (and onwards). I gather that I have to change from Terminal B to Terminal E at Logan.

I assume that AA will book my baggage through to my final destination. My questions

1) I think terminals B and E are connected post security. But will I have to exit security at Terminal E to get a boarding pass from Qatar? Especially since I want to use the biz class lounge in Doha (which may require showing a Qatar Air boarding pass at Doha).

[The airport gate may have some ability to do this too, but they often don't open till just before the flight and are often heavily crowded without a separate biz class queue.]

2) I know it's not much time, but I'd like to freshen up briefly in the lounge at Logan. What lounge does Qatar use at Logan (I've heard Air France)?

3) Somewhat unrelated question, but I original picked a QSuites seat, Boston -> Doha, then the aircraft changed to a non QSuites type. At this point, Qatar doesn't allow me to select seats, saying I should do so at check-in. Does this indicate some flux, and a possibility that I could be shifted back to a QSuites config? And to link back to my previous questions, seat selection would require going to check-in outside security?