Good call on the 2 piece, the longer tip will help defuse the air more than a shorter tip and the blast(the main noise maker of a pb gun) will be a bit softer.
However, you may want to consider a freak back with one small bore insert(like .682) to get better efficiency and a more accurate shot.
I don't suggest turning your loader off, it's not a VLocity or a torque, so if the gun isn't firing, it isn't going to make any noise.
As for the rain shield, why would you need one? Today's paintball guns, even the high end "fragile" ones are sealed from the rain. Personally, I think an e-cocker would be more likely to function in the rain than any tippman.
Instead of a stock and remote line, which is just something to get caught up on branches, why not just get a 45/45 tank? Then either run it like that or try and find one of these ASA adapters.