I am traveling from MIA to BKK via DOH in late June. I scored 2 AAdvantage award seats in business class for the MIA to DOH portion. I will have to *buy* the DOH-BKK segment -- on a separate reservation -- because AA doesn't have any award inventory for it, and seemingly can't sell me a QR ticket (I have to buy it directly from QR).

And so my one-way trip is on 2 separate tickets even though it's all on QR planes. Best connection duration on DOH is 2:25, but there's a later DOH-BKK flight that would lengthen that to ~6 hours.

Questions:
(1) When I check in in MIA, will QR check me and my bags all the way to BKK? If not, I suppose I would be forced to actually enter Qatar to get my bags and check in for the onward flight. That seems highly undesirable.
(2) Would I have any kind of protection in case the MIA-DOH flight is late? Or would they consider me a no-show for the DOH-BKK segment?

I'm wondering if I should take the 6 hour connection to guard against these issues.

Also, I'm aware that I might have to show QR proof of onward travel from BKK since I'm on a one-way ticket. Would they accept info from a different airline for that? I'll be returning to the US on EVA and will have a BR itinerary and ticket number I could provide.

I called QR to ask them but the agent didn't really know the answers definitively and said she'd get back to me. So I thought I'd ask the experts here for possibly more timely and definitive insights. Thanks!