So, I got it working well enough for me, just didn’t save anything until Step 7 of the wizard, where I have a “Validate Data” button. That button does two actions - it saves the Entity, at which time any required fields that are empty throw an error, and then it saves the Contact, and also throws errors if there are required fields missing.

I had to break out the saves into two separate actions, not sure exactly why but it worked smoother that way, I think because the contact required that the Entity object be real so that the lookup field on the Contact connected to something. 

Then once there are no unsaved changes in both of my models, the Submit button is rendered, which does the redirecting I want. 

Thanks for sharing the solution, Jack.  Yeah, that sounds like the reason you had to do the saves separately… even if the Entity model is before the Contact model, if they’re being saved in the same action, I feel like Skuid tries to save them both at once, which causes problems saving the new Contact.