Enterprise plus a signed BAA does not make you compliant. Compliance lives in the configuration. Check off everything that is true of your portal. Every box you cannot check is a gap.
Your architecture is sound. Keep the field-by-field discipline every time you add a property, because that is where drift starts.
One or two gaps.
Fixable, but close them before you layer more data or workflows on top. The longer a gap sits, the more gets built over it.
The shared-object test failed, or several boxes are unchecked.
This is a remediation project, not a settings change. Do it in order: property audit first, then integrations, then re-architecture. Never re-architect first, because you cannot design the target state until you know which properties carry PHI and which integrations are writing it.