re: Orlando late July with kids (ages 7 and 4)

Those are great ages for kids there. I would not do Magic Kingdom in the summer on a weekend, so if you will be there on a Tuesday through Friday that would be a great thing to do. Mondays at MK are supposed to be packed too.

Also, definitely consider Animal Kingdom or Hollywood studios there are tons of shows there where Fast passes are pretty much pointless, plus the big things to Fastpass are the roller coasters, tower of terror, etc that are not fit for little kids so you wouldn't have to worry about your planning either.

But yeah, as said only getting 1 day tickets are the most expensive by far. You get price drops after 2 days that are in half or more.

Spirit is just a low coast airline that only flies select days like Thursdays and Sundays to many places and once a day, so if they have a plane issue it causes major issues down the line. They will often just straight up cancel a flight. My wife tried to take it on a Friday night that I drove to on Thursday, and the flight was canceled so she had to drive down the following morning (didn't want to drive overnight as flight was like 8pm). But if it works out it could be great. If you are taking spirit, just understand this and I wouldn't book anything you can't cancel.