Establishing the list of authors for a comprehensive/review (conference) paper
The way that I think about this sort of situation is that co-authorship of an abstract and talk is very low-stakes, and there's little reason to be stingy with it.  The most important thing here is to preserve a good relationship with collaborators that you value, and so I would recommend asking your collaborators.  

If it's a collegial group with good working relation, then you'll probably get a quick consensus on one of the three options.  My own experience with many co-author situations like this is that many collaborators are happy enough to go along for the ride; a few will make constructive (or at least neutral) suggestions, and most just want to make sure their name isn't getting associated with anything embarassing---most people will only try to micromanage if you invite them to.

One important note, however: if the consensus ends up going with option #2, where some people get designated as "important", then let your collaborators decide if they should be on that list.  Again, the authorship of an abstract and presentation like this is pretty low-stakes (unlike for journal papers, where it's good that it sounds like you've already got clear boundaries drawn).  It's extremely dangerous for good relations if you put yourself in the position of telling Juan that he's less important to you than Marie.

Now, if you've got a problem collaborator who is not likely to be collegial or who is going to try to operate you like a puppet on stage, that's a different problem, and one whose resolution is likely to require very specific help and advice from some of your senior collaborators...