You are worried about bike weight for touring? What about the luggage?
I would use the saddle, stem etc. that fit the best for long tours. Not the lightest racing fit that is horrible to endure for a one hour race. I can ride any bike for 1 mile. But a bad fit or saddle will be painful and will eat power on the long run.
Use wider touring tires with flat protection or tubeless. The lighter tire may save 2 minute in a 5 day tour. Fixing flats daily will eat those savings.
I wouldn't put on worse brakes or weaker wheels to save weight.
If you want to be weight weenie, start with a light bike. Making a heavy bike light is an expensive fools errand.