I've tried using OneDrive Personal. The first problem was that the path has to be Apps > Enpass, which means it isn't possible to share just the Enpass folder. I have to share the entire Apps folder, which is potentially dangerous.
The second problem, and one I don't really understand, is that after sharing the folder and my colleague adding it to his OneDrive folder (so that is appears as Apps> Enpass), when he tries to restore from OneDrive, it says there isn't any data there.
So unless I've missed something, I can't use OneDrive either.