When you book your flight and your wife's flight they will be on 2 separate PNR's.... Just call the preferred desk and have them link the reservations and ask to have both of you assigned to the preferred seats. I just redeemed an e-tuv voucher a couple weeks ago and had them link my parents flights to mine and now all three of us are sitting in bulkhead. No problemo. But you are right about her not being eligible for the upgrade.... You could always upgrade her with miles if you get upgraded at your window.