New homeowner and forum member here. The home is about 55 years old. Most of the house has been updated - except the beige and chocolate bathroom and the plumbing. It has galvanized pipes. Water pressure isn't great, and rust sometimes settles in the lines, so I'm hoping to replace the plumbing next year. (The pipes will have to go through the attic because it is a slab house.) I figured while people are cutting holes in walls and tile to replace plumbing, maybe I should just redo parts of the bathroom at the same time.

Things I want to know:
1. Am I insane?

2. Should I get a general contractor to oversee the replumb of the house and the changes in the bathroom, or should I hire out the job by task - hire a plumber for the replumb, then someone to fix the walls from whatever the plumber has had to do, someone to tile, etc?

3. How far in advance do I need to contact potential tradespeople? I'm planning on doing the replumb early next year, and I don't want them to think I'm wasting their time.

This is what I want done:
recoat or replace bathtub (coating job from previous homeowners is peeling)
retile bathtub surround (or install 3 piece tub wall)
replace shower/tub fixtures (showerhead, bath faucet)
remove wall tile (all walls are 1/2 tiled)
add a vented fan

I'd like to keep the existing toilet, wall hung sink, and retro mosaic tile floor.