Auto-Align Post supports processing of up to 48 multiple microphones.
Pro Tools 2018.7 release broke multi-input of multiple tracks. (selecting multiple mono tracks yields separate process per track).
Multi-Input does work on multi-channel tracks (Stereo, LCR, 5.1, etc...) for Pro Tools 2018.7
Avid is aware of the issue and should be resolved in a future release.