1. Upgrade to moderate hotel, CSR vs. purchasing park hopper and/or water parks & more
These hotels have nice pool areas and slides. They've never been to WDW so they don't know anything about all the things that are available like Quest and the water parks. I'm sure they might see the water parks but I can explain to them we'll visit them next time because our tickets don't include the water parks. As long as they have a pool they'll be fine. The main parks will be crowded so visiting them two days will allow us time to do mostly everything. You are taking 6 people, that is a maximum of 2 rooms at any hotel you stay at. I would go for values.
2. Adding 6 yr old to pkg vs. buying her a separate ticket to the parks. 6 yo eats like a bird. Dining would be a big waste for her. I plan to go to one character breakfast and we can use one of our meal tickets for her. If I purchase the package for 5 can I ask that they not put dining on the package for the 6 yo? Everyone must be on the same package, as afore mentioned by many other posters, I am sure if she can't eat her food, her brother can.
3. Can I get a room for 4 and purchase the 6yo a 7 day park ticket when I arrive at the park? If you are getting a package, tickets come with it. Furthermore, if you plan on doing either early morning entry of later night activities, everyone must have a room key to get access.
4. Is there a gatekeeper at the pool and water slides at CSR? Don't know
I wanted to say you are a great aunt for taking them and allowing them about 6 mos to wish hope and dream.