The upper limit of current US scope is 86 seats. Upon merger closure, that number goes to 76 per the MOU, grandfathering in those aircraft (Mesa CRJ9s and Republic E175s) currently operating with more than 76.

Not sure about the data on the fact sheet, but none of the Mesa aircraft thus far have operated with more than 86 seats, and that was all-coach. Once first class was added to the "large" RJs, Mesa has seated 79 and Republic 80 in the dual-class configuration on the affected airplanes.