Will I be expected to reauthenticate (e.g., sign back in using Multi-Factor Authentication) throughout the day?
You will only be expected to reauthenticate if you log out of MyDTCC or if you have been timed out of the application.
If I authenticate (e.g., sign in to MyDTCC) using Multi-Factor Authentication, will I need to use MFA to access any other college resources (e.g., email, O365, D2L)?
If you authenticate with MyDTCC will not need to use MFA to access additional resources that you connect to through MyDTCC. Your computer will hold on to a token which will tell any additional accounts that you have signed in.
Does the Office 365 migration affect our use of Google Calendar, Drive, or other Google products?
No, it does not affect the use of Google.