I meant you screwed your passenger if you leave it out.
It should still be functional when you put it back on. If you are leaving it in, I would not unhook the wires just to be safe. You can just set the airbag aside and continue. Make sure you battery is disconnected because you could accidentally set the airbag off. I replaced both my airbags, clock sensor, and impact sensor (similiar to clock but under the dash on driver side) with no problems at all. I haven't tested the airbag deployment yet and hope I won't have to, but I am sure they will deploy. When you turn your key on the system runs an airbag check (flashing light on dash). If there is a problem they light stays on (such after deployment). The system could also think there was a crash from a break in the circuit (disconnected wires) and cause deployment. I drove for 4-6 months with two deployed airbags before I finally fixed it.
I am not positive if it is true, but the cover is not really paintable. The surface is different from the hard plastic that most people paint and normal paint will chip off it. I wanted to paint my whole dash laser red but the texture is not paintable. You can try it though and see what happens. I would try it on a hidden part of the dash or door panel first, or take it to a paint shop and see what they say.
Edit: If you have a ford repair cd check out dash removal. I can get u one by the way. You can remove your whole dash whithin 4 hrs and have it painted and reinstalled. I think the way most people are painting their dash looks odd. Kinda like a cockpit look. If the whole dash was one color it would look better. Just my opinion.