Personally, I would be comfortable with a 57 min layover, but others might not. If your incoming flight is delayed at all, you will miss the LHR flight.

I would ask myself this:

1. What are your consequences of flying to LHR on the next flight or the next day? Missed crucial business meeting? Missing being the best man at your childhood friend's wedding? One day of a long vacation? Are you willing to risk missing the LHR flight due to a 20-min delay on the MCO flight?

2. How do you feel about the "very long layover" in ORD, thus practically guaranteeing you make the LHR flight? Would you be comfortable leaving the airport, and going into the city for a little sightseeing? Could you just check into an airport hotel with reasonable day rates and have a room, bed, work desk, shower, pool, gym (etc) during the long layover? Would you be OK with spending that time in the Admirals Club inside the airport, using their shower, work desks, comfy chairs, etc?

3. Do you think asking for wheelchair assistance might help make the connection if you cannot run under your own power?

4. Can you connect through DFW where they have electric carts for handicapped people? MrQ has a mild disability and we use the electric carts when traveling together. They whisk you down the concourse in no time.

I don't think anyone can predict gates or concourses this far in advance. I tried that, myself, for a tight connection a couple of years ago and failed miserably.