I have a Friends & Family account at IB because I manage multiple accounts.
I had no problems connecting to the IB TWS Gateway with the Zorro plugin, specifying a user’s account number in Accounts.csv while logged in as a Friends & Family advisor. The balance information appears correctly.
But there's one problem: If I place an order, I get this error:
!Order rejected - reason:Invalid or missing IBCustAcctNo AIV-STK--0.00--SMART/NYSE--USD
I assume that this field is normally left blank for single-user accounts. Apparently you need to be more specific than that if you manage multiple accounts from a single endpoint.