1- If the couple paid their way, but someone else from the group went in their place, should the couple be allowed to keep their priority for next year since they met the obligation part of the night?
I think it would be reasonable to allow this for one year, if the couple are very loyal members. Hwever, i think it would be wise for the organisers to be celar on why they are allowing it (e.g. Couple have been members for over 10 years, it's a one-off exemption etc)
2- This year there will be four people unable to attend (in this case, it is two couples). This is very rare. When the next person on the waiting list (a couple, Jay & Kay) learned that they would get to go, they said they wanted to bring their (grown) kids, too. This would take up all four open spots, with the benefit of priority for future years. The grown kids are 30-somethings and a common part of the whole group. Then, a couple that was already "in" (Don and Lou) and have attended for several years said they want their kids to come-- shouldn't their kids have a chance before the other couples' kids? Is this fair? The waiting list has always been informal; saying "Jay" rather than "Jay and Kay, and their kids."
This 'feels' unfair to me. If I were on the waiting list, I would be pretty annoyed to find that someone else had been allowed to jump the queue just because they were related to someone. Presumably the adult children could have been on the waiting list themselves, had they wished?
3- If the next person on the list was not married, should they get to bring a SO who is not part of the group?
It sounds like the kind of thing where people would are likely to attend as couples if they were are a couple, so this doesn't seem unreasonable to me, however, I do think that the person on the waiting list should let the organiser know they are half a couple as soon as that becomes the case, and perhaps decide whether that means that if only what spot comes up, the person on the top of the list gets it and their partner has to wait or whether you simply give the spot to the single person highest on the lsit, as you are filling a single spot, not a double one.
However, with all of these scenarios, I think the single most important this would be to be consistent, and as clear as possible about how things will work. For instance, I might not agree that some people should be allowed to miss a year without losing their place, but if there was a clear rule that this was only available to people who fit specific criteria (e.g. members for at least 10 years, no more than one missed year per person per decade etc) it would be better than if it is (or appears to be) well, normally if you miss a year you go back to the bottom of the waiting list, but as it's Bill and Ann we'll waive that rule because they are Bill and Annie and they are the friends of the organiser.
(If the reality is that Organiser takes the view that it is their event and they will do as they want, that is OK, but they need to be upfront about that as well!)