I am going to be travelling from Delhi to Milan with my wife in April this year. I have some upgrade vouchers I wanted to use for moving to Premiere, so I called the customer care and asked them if there was availability on my preferred dates. The rep. told me that there was only 1 seat available (then) on those dates. I am quite clueless as to how this works. Could the experienced FTers please help with the following:

1. If I book two tickets on the same PNR and take the upgrade offered for 1 seat, will I be on a priority list for upgrades over someone else who is travelling alone?

2. What are the chances that I would get the second upgrade also? When would I know for sure?

3. Are the upgrade vouchers refundable? Asking because if both of us don't get upgraded, I would rather cancel the upgrade request and travel Economy together than 1 Premiere and 1 Economy.