Engineers behind the Zero are all deceased now. People are what make a company, and theirs has very little experience developing transport jets.
But with billions on the line with the success of the project, I think the deliveries happen.
Compass flys E175s with MTOW of 89k lbs. I'm sure if the weight of the MRJ9 isn't fixable, a clause will be agreed to for the specific type, still limiting it to 76 seats. Some agreement to parking more 50 seaters or replacing old 70/76 seaters. If all else fails, convert to MRJ7s to replace old CRJ7s, fly routes commonly done by 50 seaters.