Just an update. I called and got nowhere. At first they said they could apply them if there was space available and there was but then during that process (which included me waiting for about 20 minutes), they realized their mistake and shut me down.
I then tried to use them on a flight I'm taking with my wife and kid flying on a companion pass. Again got pretty far along before the agent realized you can't use them with companion tickets (I didn't know that either).
Finally, I emailed Delta today and received a pretty quick response saying that they would not extend my certs by 3 months as I had requested. Disappointing to say the least.
I also didn't realize you can transfer them to others anymore. I have to say, I generally keep up with the program but the amount of changes they make to these things makes it pretty hard to know exactly what you have unless you read the terms each time. A little frustrating as a premium traveler and the loss of those two GUCs means I will probably switch to BA sooner rather than later (I'm moving to London in a few months).
In positive news, I was able to use my 2015 GUCs immediately to upgrade my trip to and from London in a couple weeks
