There are some VERY good car sprayers out there, but spraying cars is very different from spraying guitars. Cars need thick coats to protect them from the rigours of all weathers with dirt and grim at speeds of over 100MPH, but guitars need thin coats that offer protection, but don't seal them in a thick coating of polyester that damps the body and stops it from resonating properly. To give you an idea, when I was taught to spray a guitar we would put on between 20 and 30 coats and the total thickness was thinner than a single coat on a car. As long as you make it clear to your paint guy that you need to keep the overall thickness of paint down to those levels, he should do just fine.
And it's always good to take the opportunity to try some different mods too. P90's work well in tele's, and this is the perfect opportunity to do the routing required to fit one. Another option might be to look at a P90 in a humbucker size package, or at least rout for a humbucker, as that will give you more options in the future for the same amount of work now.
Off the top of my head I can't think of a tele control plate replacement drilled for a 3 way toggle. Mechanically the tele style switch is just as robust as a Gibson style toggle, and it does offer more flexibility in wiring (and a 5 way 4 pole switch will drop in with minor woodwork to the control cavity and give loads of extra wiring options). However, a Les Paul style toggle should drop in with a little woodwork in the cavity and leave enough room on a tele plate for 2 volumes and a Master Tone. You could probably do the same with an SG style angled toggle but it might leave the 3 controls a little tight together, but it would work fine with 2 volumes and no tone. And stacked pots might give you more options too, so you aren't totally tying your hands if you go that route.
Your painter should be able to help you here, he probably knows a few local machine shops who could make a custom plate for you using the existing tele plate as a template. Even if you need it polished and plated it could work out a lot cheaper than you might think. You often find that the guys in the workshop are genuinely interested because they've never done anything for a guitar before.
And if you have any more questions, just ask.
When the going gets weird, the Weird turn Pro.