If AS moves to C and N, there are two possibilities for the Star Alliance carriers:

1. Move to D (and use the current BR as a Star Alliance Lounge)

2. Move to A (and use the old AC and CR as the US and CO lounges respectively or use one of them as a combined Star Alliance Lounge).

Honestly, #2 seems more plausible to me. Move CO down to the end of A where DL was, put UA where AA currently is, and leave US where it is (or slide down 1 gate to accomodate all of UA's flights).

AA, Frontier, and Midwest could move to the D concourse.