I know this is important to you, and you want it to be important to them, but I think somehow part of the magic is gone when the people involved know you’ve actually been married for a year already and that you had a (small, private) ceremony. I know at the time it was for the insurance, and I understand that this didn’t happen the way you wanted it to. I feel for your feelings and wishes that weren’t met, I do. But, I think expecting people to pay to come from far away, pay for a dress, etc when they know it’s already done may feel like a lot to someone on a budget, even if they are your “best friend.”
The paragraphs about the situation and how everyone is letting you down do make this sound like a lot of expectations not voiced, nor met. It doesn’t seem to me, (IDK) that you clearly expressed your expectations. It sounds like you were like, “Yeah, sure, the anxiety,” and on one hand you know your friend well enough to know what she’s able to do and what not- and on the other hand, you are disappointed that she can’t overcome her condition to make a speech that day.
You have to accept people where they are, not what you wished they would be.
Make an alternative to a stuffy ceremonial wedding. Plan the day with all of you in consideration and take the pressure off. Is it a “wedding” or celebration of all the live around you?
I know I’m a party pooper but that’s my two cents.