Thank YOU!!! I am grinning ear to ear!!!

the CMs at the Special Reservations number (listed in the disABILITIES FAQs) are excellent for questions about rooms, resorts and tours. That is their field.
For any other questions or for asking disability related questions of any kind to Amy other phone number,
I would advise taking anything you are told with a HUGE grain of salt. The CMs are at a call center and may not actually have any information about what you are asking. There have been situations where people have posted they were told all sorts of information that those of us with a lot of experience knew were wrong. After going to WDW and trying what they were told, the posters knew they were wrong too.
The same thing happens all the time on the Resorts board, where one person posts they asked a question and were told xxx and another poster asked the same question and was told yyyy. And these are usually fairly uncomplicated questions about things like dining plan, where rooms are and check in.
My guess is that you will have no problem at all with the attractions that don't have any warnings (with the possible exception of Soarin' and Peter Pan because both of those go up in the air, suspended). There may be some of those attractions where space in the ride car is a problem - you can find links to pictures of ride cars in post #3 of the disABILITIES FAQs thread.
I' m basing the guess on knowing that those attractions have a place to put items at your feet - we have brought backpacks on them and people have posted in the past about bringing crutches, canes, etc.
My best guess is that the thrill rides ( those with warnings) will be a case by case basis and will be up to the individual CMs at the attraction, based on what is available and how well they think your equipment will fit/stay in place. You can always ask for the supervisor at the attraction if you think it will work but the CM at the attraction doesn't.
I can't post a list of attractions with warnings right now because I am writing on my iPod. You may also find some information in eternaldisneyfan's trip report linked in post #3 of the disABILITIES FAQs thread in the alphabetic section under wheelchairs. Their family had a variety of challenges, including ventilators.
There is not much info about what attractions people went on with oxygen, so please let us know when you get back. My guess is that most people on oxygen don't go on the thrill rides because of other health concerns, but that is just a guess.
I'll do some poking around on Friday to see what mire I can find.