Have a OW redemption ticket in J (DFW - PHL - AMS).

My initial booking was with a 7/8 hrs+ connection at PHL, but had being rescheduled by AA due to cancellation, and they now put me with only 1hr connection at PHL.
I understand it's still within MCT at PHL, but I had already planned for the worst of a missed connection and/or missed checked bag.
Tried to check for award availability, and there's none to make a ticket change, so I am now looking to standby any earlier DFW-PHL flights.

Questions:
1) Can I standby all the earlier flights at once (ie. through the app/internet (if allowed)) or request at the airport Check-in desk? or I had to standby one by one only after the 1st standby flight knocked-me off?
2) Would standby put me down to economy class (assuming seats available)? (Perfectly fine for me as long as I can board the Int'l flight with my checked through luggage)
3) I will have 2 checked bags, and it seems that I should approach the check-in counter agent before any bag drop, to ensure I got a stand-by tag on the checked bag. Did I get anything wrong on the procedures? Also, I assume the checked bags should fly together with me on the same plane, no matter if I successfully standby or have to stick with the current schedule.

Thanks in advance for all the experts and the lovely community.