Florida honors your Michigan CPL by recipricocity agreement, you're fine there. If you have a Michigan state DL or ID, I'd recommend you use that as Floirda does not honor any NON RESIDENT licenses from other states. In other words, so long as you are a resident of Michigan and can prove it, your CPL is honored here. But, if you are NOT a resident of MI, and hold a Michigan CPL, while it's valid in MI and other states perhaps, not here. Leave the FL ID at home, that's the kind of thing that could just confuse things and hold you up while folks get UN confused. :quirky
As far as Disney goes. It's long been decided by most that it's pretty much up to you. Disney property is private property and NOT prohibited by Florida Statute. Disney does have discreetly posted "no weapons" rules in different places. You almost have to look for it. But, in Florida a "No Guns" sign has no legal weight. Similar to the "no shoes, no shirt, no service" signs you'll see on business doors. You won't be arrested for ignoring that sign, but, you could be asked to leave.
As of last check, no metal detectors. Security will root around in your bags with a stick and send you on.
So, in the end, carry is up to you, but, make sure your conceal methods are solid. All those people stuffed into small lines, rides, etc, combined with all the moving, sitting, and shoving you'll be doing, you'd better have your conceal "A" game going.
In the end, are you breaking the law? Nope. Are you ignoring private property owner's wishes..yep. Choice is yours. I'm not going to tell you to break any rules, even if it's private property owner rules.
Rumor has it, though, that Disney will allow you to lock up your firearm in security if caught. But, I can't confirm that. Never been caught myself.