we are on the same side. I am first documenting the Meraki REST API material with Postman, Python and Github. I attach some links that can give you more idea. We can share experiences in development if you want.
I'd be delighted to be wrong, but all I'm seeing is getNetworkMerakiAuthUsers (all users) and getNetworkMerakiAuthUser (one user at a time). Nothing to create users or delete them.
Creating and updating via API would solve a problem for me, so long as one could authorize for client VPN... My boss would go for a widget that my helpdesk could use. My boss will not go for SAML, for reasons.