My Business/First SAAver award flight from AMS-PHL-DCA-home was canceled this morning.

Was rebooked for tomorrow AMS-LHR-PHL-home, with LHR-PHL in Business.

The AMS-LHR portion is in Economy and the final leg from PHL-home is in Main Cabin Extra. Am I able to be put on a list if the Business/First seats open? Is there any mileage compensation for losing First on one domestic segment? (Airport staff was extremely busy and AA repeatedly hung up calls, saying to call back later).

I checked in online already but do not yet have boarding passes in hand and must present my passport to BA staff. When I wait to do this, am I still able to stand in the Priority Lane equivalent for BA, even though AA booked me in an Economy seat for this first flight?

I have used the lounge in the past for a similar flight (BA economy, but LHR-USA portion in AA Business) and believe I can still access the lounge in AMS, correct? I would have been able to go this morning had my AMS-PHL flight not been canceled and the AA rep told me I’d have access, but wanted to hear from the experts here.

THANKS!