Welcome to FT.

Firstly, have you checked availability, as CPT is hard to get seats and this topic might be academic.

Assuming there is availability, if you have an amex 241 voucher then the "companion" doesnt need to be within the Household account. Other than that its the key clause of a HHA that redemptions can only be for those within the HHA. Obviously, if your friends were also living with you for example, they could join your HHA.