@Alkemichar
Of those, I'd recommend (strongly) the XDeep Zen. XDeep does not make a bad product (no jacket style BCDs! ). I think it is fairly clear I hate jacket style BCDs (something breaks, you are out a BCD and too much floaty material - I'm a minimalist). I own the XDeep Stealth 2.0 Tec, Hydro 50 wing, regular XDeep bp, and used to own the XDeep Ghost (which is close to the Zen).
People who consider BP/W to be tech gear are simply wrong. Lots of people, many who will NEVER dive tech, dive a BP/W for all of its benefits. It is how a minority of instructors teach their students in open water. I would recommend at least trying one. It is merely tech capable. You'd still have to get a wing for doubles to make the jump. You do not want to dive a wing meant for doubles on a single tank. Unless you REALLY like tacos.
I'm not sure what kind of assistance you will need. There are plenty of videos (ISE has a good one) for setting it up.