The experience on the bus is the same from WDW or the airport. Not sure what part of riding a coach bus is "fun", but then I'm rather immune to pixie dust.

Also I grew up on a Greyhound b/c my dad was a driver, so riding a bus is layered with very odd memories, no matter if the wrap on the bus is
DCL themed.
From the airport it starts boarding at 9am. From WDW resorts your meetup time to get ready to get on the bus might start as early as 11:30, which means you're getting to the port later ahn if you leave from MCO nice and early. That makes a difference to us. At WDW you get a notice letting you know what time to meet, and you get it the night before. We didn't actually get that notice. So...well organized is NOT the phrase I would use for the experience. We then met at the time where we signed in then sat around for over half an hour until they finally rallied us to go towards the bus. Again, not very well organized IMO.
Yep.
OP I would WAY rather take the DCL bus back to the resort if it's a choice of before or after. I just want to be at the terminal early, not sitting on a bus knowing that others have been onboard for an hour already (our first DCL cruise my cousins texted that they were onboard before our bus's engine had started). That's not as important for other people. Decide what you want.
But really, it's so expensive that checking out car rentals is a good idea. We like the Alamo/National/Enterprise setup they have now.
IMO....if you are coming in when there's not much light left of the day, just stay at the Hyatt. If you'll have light and possible beach time etc in Canaveral, head to the coast.