Can our bags be put on the Magical Express to Pop Century but we take an Uber to get to Magic Kingdom quicker? Our plane lands at 6am and we want to make it for EMH at the park. How long does it take to take a shuttle to an off airport car rental place (too expensive to rent at the airport for us)? Could we make it on the rental shuttle then over to the Park in 2 hours?
Officially, at least one person must ride DME in order for your bags to be transported. I can’t answer your other questions.
Check out carrentalsavers.com - I have always been able to get on-terminal deals there that beat the off-terminal ones. And keep checking back regularly - if you find a better deal book it and cancel the other one.
I would say almost definitely no. You need to take the tram, get the shuttle and the car, then drive to the TTC during rush hour and then take the monorail or ferry. You might be able to get there sometime during the EMH, but definitely not prior to rope drop.