Yes, I agree. You and your son have done your best to try to make this happen!

The airfare was a bit of a wrench in the works, or snafu, that complicated things. But I think you figured out how you should handle that.
It does seem that this other mom (parents) have been non-committal, and I would not want to let that last long.
I think that you, your son, his friend, your DH and everyone else involved, deserve to know what to expect or look forward to, or not.
I do have to admit that the whole hemming and hawing and non-committal thing is just one of my pet peeves. So, I am objective enough to acknowledge that.
You are putting a lot of time and money and effort into the trip, and they should respect that.
I think it would be just the saddest thing for somebody to cause their almost adult kid to miss out on something like this, because 'I wanted to be first'.
Me-thinks that if the parents wanted to take their children to Disney, if they haven't made this happen at this point, maybe that ship has sailed.
Didn't somebody try to make a comment to 'me' about independence?
I don't think I am the one that should have been directed towards.