Ok lemme see if I understand. The brewery is giving you second runnings and you can add more wort, lme or dme and do whatever you want to it. Then submit it for judging, Right? I would tend to think that LME , or HME would be your best option. Otherwise a 2 Lb mash is way small for a regular mash tun and would be pretty difficult to get much usable wort to add to what they have already given you. With the variety of LME and Hopped LME you could turn it into just about anything at whatever SG you wanted it to be. Then your yeast selection and hop schedule will be entirely up to you, as well as adding fruit or berries if you wanted also. Second runnings are generally lower in fermentable and lower gravity so they will definitely need some help and I don't really think a 2 pound mash is gona be enough to make much of a difference either. Just my take, I could also be way wrong too.