Damn that's going to be cool! And I like the 2 Woodies!
If I may.. I don't think you'll be happy with the cable / remote master cylinder.. I tried it on my bike and it was only a tad (if that) better than the drum brake.. the cable pull ruins everything.. makes it really soft and not responsive.. I then switched it to fully hydraulic and it works as it should..
Your bike is looking like it's going to be heavy and fast.. and I think a real, solid front brake would benefit you!
You don't want to just run the hydraulic like from a master-c (they make headset mounted ones for Lambretta headsets) down the fork and to the caliper?
Anyway, really excellent project!