I'll give you my opinions, good or bad, LOL.
1st, no sealant is required on the threads since it doesn't seal through the threads. The flare of the line mates up to a flange inside the fitting. When tightened together, that's where the seal is made.
2nd, To speed up the bleeding process, bench bleed the master, then gravity bleed the rest of the system. This will get you to the starting point of bleeding brakes. It let's you know that fluid has reached each wheel. Prefilling won't do much good since it will be all bled back out in the bleeding process.
3rd, you could paint your lines but do it after all the brake work is done. Brake fluid is an excellent paint stripper.
4th, get yourself a one man bleeder kit from a parts place. They work and keep the mess to a minimum. Also be sure everything is properly adjusted so you don't get fooled into thinking you still have air when actually it's poor adjustment,
Good luck,
Scott