To my knowledge it is possible to integrate Exchange ECP and OWA with ADFS on-premises.
Here is a link about how to achieve this: Use AD FS claims-based authentication with Outlook on the web
While to enable MFA on ADFS, I suppose the only supported method without third-party solutions or Azure is Certificate Authentication.
Here is a link about this topic: Configure Additional Authentication Methods for AD FS
Kindly note that: since we are not very familiar with ADFS, if you have further questions or need help with ADFS, please consider adding the tag "adfs" to your question to post in the ADFS forum.
It would also help you get better support.
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