Can I ask why the 3 training managers can't do the onboarding? It's good to keep close to the ground but I feel you'd be better balanced without those duties. Who manages client requests when you're facilitating? It would be likely be easier for staff to develop relationships and establish expectations from those that will actually be responsible for their performance. Maybe downgrade to delivering a couple of components than the whole thing, eg non compliance, performance issues etc.
As for the title, I think a lot of what you describe is engagement (staff and clients). So I'd go for a name with that in it. Maybe Senior/Executive Engagement/Relationship Officer/Expert/Manager/Specialist
Good luck, sounds like a great company to be apart of!