Once a tire is aired up and seated on a tubeless rim, letting most of the air pressure out shouldn't be a problem. I've run multiple non tubeless specific tires on a tubeless rim and had no problem with low pressure once it was seated. I deflated my tires almost entirely to fit my bike into a box once and the tires didn't unseat during the flight. I would not, however, use non tubeless rims. Tires don't seat on them, and you will lose your seal/sealant. That would be a mess and a PITA.
As for the road tires, I haven't used them personally, but from what I've read, they seem to be a different thing to deal with all together compared to higher volume mtb type tires.
Personally, I'd run tubeless and bring a couple spare tubes as suggested above. Chances are you'll save yourself from getting any flats. Worst case, you get a flat and put in a fresh tube as you would do anyway. My one caveat being that this applies strictly to Stan's sealant. I've done a lot of reading on the subject. Stan's seems to be the way to go. I tried it and it works great for me, so that's what I stick with.