That growth on your azalea as you got it was amazing, including the backbudding. I would have said that if you do that last idea, the transition between your fat trunk and the somewhat thinner branch that becomes your new trunk line, won't even out and become gradual within 5 years. But maybe with some really really strong Florida growing seasons worth of growth budding off from that currently thin branch, maybe it will even out enough?
I think I would try to chop the intermediate thickness branch, build an apex on the fat trunk, and then see what to do with the thin second trunk. A bushy apex that doesn't show any branch structure can kind of hide that it was chopped and thus suddenly stops.
Same with saying that 5 years is too little to grow an entirely new branch, for example using that shoot at the base of your proposed chop.
Even if 5 years is not enough, you may want to try to go ahead with it anyway, because it could give you the best long-term results and this competition is just this random thing on the internet. But with all that backbudding on the fat branch... why cut it rather than use it? I think I would cut the branch going to the left on your last image. Keep the fat one. The backward facing one seems to have a nice natural curve to it. (I was going to say 'cut the backward facing one' but then your Y-split looks so 2 dimensional). You will have a scar right on the front of your trunk, though.
