Have you been to Disneyland and Disneyworld? Then you've seen the best Disney has to offer. If you are a real fan, though, it will probably be interesting to see it in French.
There are only a few sights that have long lines. With the Pass, the only lines you can't skip are Notre Dame Towers (expect at least an hour's wait) and Sainte Chapelle's security check. Sometimes the Pyramid entrance to the Louvre has a separate line for Pass holders, but not always. Use the Carousel entrance instead. There's hardly ever a line at any of the other sights except the Orsay. If you want to rent an audio guide, you may have a short wait anywhere, never a long one. The big advantage of the Pass is the convenience of not having to stop and pay at each sight and being able to pop in at a sight that you happen to be passing, without debating whether it's worth the price. The flip side is that if you go to a sight that turns out to be uninterested or crowded, you can leave and not feel that you didn't get your money's worth.
Passports - opinions are divided about in half here. Some feel it's safe to leave it in the hotel and find it uncomfortable to carry in a money belt, others prefer to have it with them. Take your U.S. driver's license with you to use as photo ID. You may be asked to leave it as security for an audio guide rental.
I don't like to use a credit card because I don't like to carry it where it's accessible. I take large amounts of cash from an ATM, then keep most of it in a money belt (or hotel safe) and about €40-50 in "ready" cash. If I run low, I can duck into a corner and get another €50 from the money belt. A credit card transaction requires a second trip to the money belt to return it.
Depending on what day you arrive and leave, a weekly Navigo pass can save you a lot of money. It costs about €5 to buy the initial card (and you need a small photo). Then you put a one-week pass on it. That gives you unlimited travel (within the zones you choose) for bus and metro travel. The "catch" is that it runs from Monday through Sunday. If you're in Paris for 6-7 days, it's well worth it. At 5 days, it may be a break-even proposition, worth it for the convenience of not using the individual tickets and also being able to hop on a bus for 1 or 2 stops. You can get it at most metro stations that have an agent on duty.
Lastly, the Pass. You said you have a list of 25 sights. Trust me, you will not see them all. The Pass is for 6 days, and you'll use one just for Versailles. That means 24 sights in 5 days. You simply won't have time to get to them all. And in trying to do that, you'll be indoors and miss the best of Paris - walking along the streets, strolling through the parks, window shopping (whether it's upscale fashions, artistic pastries, or antiques or just kitschy souvenirs). The price of the Museum Pass is €69, the Paris Pass is €197 (on sale). Pay separately for Montparnasse and the Vedettes du Pont Neuf boat ride. Also pare down your list. I'd make 3 categories, must-see, really-want-to-see, and if-I-have-time. Then group them by area You can use the last 2 digits of the zip codes in the addresses to sort by arrondissement, that will help but use a map too. For instance Tour Montparnasse is in the 15th, but very close to the 6th. The museums you listed in your original post (#3) wouldn't make my list until my 3rd or 4th week in Paris. Don't stress about trying to save €15-20. Focus on making the most of your time in Paris. Think about how much you are spending on airfare and hotels. If those few euros will give you a better experience, spend them.