My wife and I both wanted to use Enpass on our shared iMac. Is there any way to do this? Either install another version with a different master password or even better in future updates be able to put in different master passwords to the same app and have it unlock different vaults?

Are you both using the same user profile?

Mac users? No. But if it’s the only way to do it we will. Do you think we could have different vaults as different users?

If you had a user profiles each you would have separate local vaults, you would not (as far as I am aware) be able to sync them to the same place as the sync'd file is just called Enpass.  One account would override another, but if you each has an account with Google Drive then you would be fine.