Some comments from an RC flyer:
First, this all looks very informative. I didn't catch any technical errors in your presentation at all.
Second, you can buy aileron 'Y' cables at the hobby shop that will work just fine as an ESC 'Y' cable -- you just need to snip the red wire to one ESC. I think that for a 4-engine setup you're better off soldering something up, though.
Third, you mention the throttle cut on the transmitter in passing. If you can set up your transmitter to control the throttle cut with a toggle switch then you shouldn't need to dink around with the trim each time. It may be worth a look in the instructions. Every computer radio is different, so even if a Tactic won't, some other brand might (I can't speak to any computer radios -- I get by just fine with a 72MHz 4-channel, no-computer radio!)