1. You usually have to collect your bags and drop them again on a belt just after customs but I noticed last week in MIA that there didn't seem such a thing as "customs" anymore. I still assume you'd need to do that.

2. Yes, from a bag point of view. Tight from an immigration point of view. There were issues with the ESTA system last week and the APC terminals gave most pax a cross across their print out meaning we all had to queue for a manual immigration process. Queue looked massive but ended up taking only 50 mins. I've queued at MIA immigration for 3 hours in the past (pre APC) and the airport / arrivals process can be an utter disgrace. However, the APC terminals have helped and I have arrived in MIA before and immigration was a breeze taking 5 mins via APC. So it's difficult to tell in advance if you will be fine.

3. Yes. If all on th same ticket, they will rebook you and MIA MCO is fairly frequent