Will personal accounts be able to use SSO for Teams App?

[AdamCL]

I am in the process of transitioning our apps main interactions from a web site to a Teams app. 

After the user installs the app, I would like them to be able to authenticate or create a new account within my service utilizing the SSO functionality. 

I was looking at this comparison sheet of Teams subscriptions https://www.microsoft.com/en-us/microsoft-365/microsoft-teams/free and it looks like personal accounts do not have SSO support for Microsoft Services.  

Is this limitation just for Microsoft services, could I still use t Microsoft as an identity provider for this user?  

Related, can I still get an oauth token to interact with Teams on behalf of the user?

[#2]

@AdamCL No, SSO only supports the same account that the user has signed into Teams . If you wants to authenticate the user with a different account then you need to use our popup auth flow documented here:https://docs.microsoft.com/en-us/microsoftteams/platform/tabs/how-to/authentication/auth-flow-tab