Finally an update. We've been waiting on insurance to come and officially assess the situation, but now that they're gone we have the go ahead to start the process of fixing the problem.
We'll be removing all exterior wall drywall, the bat insulation, mold remediation, adding closed cell spray foam, and re-drywalling. That will bring us back to the point in the build we were when we discovered the issue.
This is the document on hybrid wall systems that was shared with us by the spray foam manufacturer:
We still feel that spray foam is worth the extra expense for your build. However, we encourage you to educate yourself so that you know what questions to ask a company before hiring them. We also encourage you not to tackle this project on your own. There are too many critical factors that go into this process to ensure you won't have the same problems.
https://youtu.be/mVEfdVhaTDY