You can book it on your account and use the e credit and use the companion code. You either have to be the travel arranger/buyer with the code OR be one of the 2 travelers on it unless things changed again. Doesnt matter who books the gold passenger, if theyre MP info is in the reservation they get the same benefits. Your wife would also be eligible as the companion upgrade so if everybody wants to sit together and not be upgraded, be sure to check that box off that declines to be on the upgrade list. She would also receive free bags as well so to save a few bucks you might want to make sure the gold and her both check 2 bags each 50 pounds and under and then maybe 2 other travelers wont have to check a bag and pay for it. As far as UG certificates, you probably arent going to find 5 open U spaces