Personally, I think it sounds like it might be a lost cause. It sounds like the delays in PHL were due to weather, in which case AA does not have an obligation to reimburse you. It sounds like the delay in MCO, which resulted in you being stuck in PHL, might have been due to a mechanical (and would be AA’s fault)—but unfortunately without any documentation that the first flight was delayed due to a mechanical problem, it’s going to be an uphill battle. Next time, it would be a good idea to ask the gate agent in MCO for a printout that indicates the delay was a mechanical delay, especially if it looks like weather down the line might be an issue. Additionally, a sympathetic agent in PHL might have been able to give you a hotel voucher at the time.

I think the best course of action now is to see if the credit card that you used for the tickets has any travel delay protection (many of the travel credit cards do). That, I think, will be your best shot at recouping some of your out-of-pocket expenses without a protracted (and potentially costly) battle.