Account for joining multiple meetings with different Username

I would like to join multiple meetings programatically using single account ? What kind of account plan will I need ?
Should I use join as API user using API Secret and API Key, or as a Normal User ?

If, my account has been invited to a restricted meeting, will I be able to join it as API user, or I need to join as Normal User only ?

These are the few queries that I have related to joining multiple meetings.

Please contact with the sales.