It sounds to me like you've got a pretty good idea about the lineup, but I might be able to add a few thoughts...
The 2013 Vegas has significantly more power than the 2012. For the last several years running (perhaps it's always been like this), the Vegas has had about 1m less power than the Rebel. For 2013 they are almost on par. The new Vegas has significantly more low end than previous years.
At the same time, I've historically thought of the Evo as having about 1m more power than the Rebel, and that seems to hold true for 2013, so the Evo will still give you more pure low-end power than the 2013 Vegas, however it won't be as dramatic a difference as in years past.
As far as the Evo being an all-around kite, it's true, but that doesn't mean that it is a slouch at freestyle. I've had some team guys switch from Vegas to Evo for a session to test it and remark how they were able to get the slack to do all the same tricks as with the Vegas. In comparison, most freestyle guys will say the same thing that you did about the Rebel... It is too forgiving and tends to pull too consistently to work well for unhooked pop-and-slack moves. Both the Evo and the Vegas should be good for this type of thing.
Just as a little addendum, the 2012 Evo and Vegas will both give you the slack you're looking for, but the 2013 Vegas has really stepped it up in this regard. The most slack I've ever gotten in a kite.
As far as kiteloops, I'm assuming you mean unhooked... I tend to think the "can you loop them" question depends more on you than on the kite. If you mean unhooked kiteloops, at 12m, they will both work great. Even the 14m will be fine... it's just a matter of timing. If you are talking about a hooked in kiteloop where the kite catches you on the way down, I'd say that the Vegas will probably be the quicker to climb back overhead, but I've never heard any complaints about the Evo, so I don't think that it would be bad. I know the 12m Vegas from 2012 is fine for hooked in kiteloops, and I know that the 2013 is even quicker to catch you than the 2012, and as I said, I'd imagine the 12m Evo to be fine as well, though I think the 14m might be pushing it in either model (though I know guys who kiteloop the 16m Dyno, so anything is possible).
As far as waves, the Evo is meant to be a wave machine, and the Vegas is not. However I just got back from a week of wave kiting in Maui and I was on the Vegas the whole time and thought it was perfect (and I used the 2012 Vegas in the waves as well with no complaints). If you're unhooking on the waves, either kite will work great, though the Evo will probably have the edge in terms of drifting and quick relaunching. If you're staying hooked in, you may find that your Rebel gives you better depower (the Evo especially has tons of grunt and can pull you off the wave) and will be more reactive when hooked in (the Vegas especially seems to lose it's reactivity when depowered or running down a wave... It drifts ok and stays in the same spot really well, it just doesn't want to respond to your input... This can be good or bad depending on what you're looking for in a wave kite).
For boosting, either kite should work well, but again maybe not as well as your Rebel, though I have lots of team guys who swear by both Evo and Vegas as boosting kites. Feedback on 2013 models seems to be that the new versions both jump better than previous versions, but they were no slouches to begin with. In general I tend to think that the Vegas will pull you up high and quickly while the Evo will give you better hangtime, but I'm really not a good judge of how or how well a kite jumps.
Anyway, as always, your best bet is to demo the gear, but it sounds like either the Evo or Vegas will work for your needs. As you are coming from a Rebel, you're probably used to the positive feedback of the 5-line direct-connection kite, so you will probably feel more at-home with the Vegas, plus you already have 5-line bars. For the sake of the bottom-end, I'd recommend the 2013 Vegas over the 2012 or earlier, but in terms of performance, they should all do what you're looking for. If you go with the Evo for its grunt, either the 2012 or 2013 should fit the bill you're describing as well.
And as a side note, I know I'm really pushing the 2013 Vegas here... It's not me trying to sell the newest stuff, it's that the kite has just had a huge redesign and I just got done with testing it for a week and I'm astoundingly impressed with what they've done to that kite. Waves and freestyle I was completely stoked with it at all times.
Hope this helps and if you have any other questions feel free to hit me up.