I do not think this requirement can be met with Azure AD. Azure AD issues tokens for users within Azure AD for applications integrated with Azure AD. If the application is dependent directly on the username and password coming from the native app, Azure AD cannot act as the IDP.
If you can figure out a way to integrate the app with Azure AD, then you can use CA policies to prevent the users from installing this on their personal devices.
I know this is will not help you much but this use case is not feasible with Azure AD.