Yes, this is possible: https://documentation.meraki.com/MV/Advanced_Configuration/Restricting_Access_to_Cameras#Step_2:_Vie...
If you show them just the Vision Portal, that's what they'll use, as the full Dashboard won't allow them anything extra anyway, given their camera view only permissions.
Google I think adhere to using an exernal SAML IDP as the recommended way to do SSO - I don't think they are themselves an IDP (happy to stand corrected, if so). Maybe try Okta - and use this (maybe also with Duo for 2FA?) for Google + Meraki + etc. etc. (anything else supporting SAML)