Jen

You are flying with Etihad not another airline who codeshares with them. They'll want your name as it appears on the reservation. The PNR number will be your main booking ref or perhaps the airline booking ref if they're both 6 digit alphanumeric you can try both to see which one works. I guess the Etihad Guest Number may well be the ticket number (is yours 12 digits) ? You could always email them your query. Graham will know he's done it