@shudson said:

Any tips for the best way to take two connected faces and put each on a different layer without creating them separately?

πŸ˜†

Two faces touching at a point or sharing an edge or more. Double click on each face and group (or componentize), one after the other. Assign one of the groups to a different layer. The shared edge(s) goes with each face into the group. With both layers "visible" the appearance is no different, but they will not act like related geometry any longer.