Pick up a copy of the Higley book There are No secrets, Helped me a bunch as to what is easiest and best in just about every application.

As to your question

You can do the stabs either way cover first then install or install then cover. The second option just makes it harder to get the fuselage right if you're trying to do it in one piece.

Paint them off the plane, prime, color, clear.

I have done both, covered the tip and cut the plastic of at the tip, just depends onwhat you want. The uncoverd tip works best if the tip sticks out over the wood structure of the wing.