“Does Rambam or Abarbanel suggest that people spend their lives wagering on who is the preferred Moschiach candidate and base their lives on that?”
There is an idea of looking around in your generation for someone fit to be moshiach. Various seforim bring that this was a custom throughout the ages(especially chassidic ones). The sefer sdei chemed brings this custom. Likewise infinite books exist of people doing this. There are two added points tho. 1. There is something further where aside for being worthy of it should the time come, u also have done a certain amount of things which give u a chazaka that u are moshiach, at that point its likely important to spend time discussing this because that likely entails obligations to the one with the chazaka in terms of belief or action. 3. There are lubavitch specific hashkafas based on the rebbes words which are playing a role here. I think the convo will be more constructive if we separate issues and get agreement on if its allowable as an orthodox person for u to believe in moshiach min hameisim of any variety and be considered not being stupid. I sent a couple sources earlier along these lines but people have been more interested in talking about the rebbe.