Full length cable housings = bad idea. Too much housing compression.
Friction shifting is cute for a tiny number of people and very much not cute for the vast majority of people. There is a reason why it died out within 2 years after Shimano introduced SIS index shifting.
Mechanical disc brakes are no better than V brakes and prone to endemic squealing.

The bike market is in horrible shape at the moment. This is a very bad time for you to be selling your own line of bikes.