Just about to answer this, but pipped to the post..
The front mech should have a 'Trek specific' barrel adjuster fitted to it, and the threaded bolt is indeed a cable stop. You can just about make it out in the picture below. No idea why they did it like that though :?
I’ve stripped it down and am now waiting on a few new bits to arrive. Biggest problem I have at the moment is that the stem is stuck fast! I’ve been soaking it (as best I can) in WD40, hitting the stem with a mallet every now and then, but it still won’t budge!
I’m going to reattach bars and a spare front wheel later to see if I can lever it loose.
Should have been an easy bike strip and rebuild, but it’s proving a pain!