Adding extra DME to NB kits?

I just received a couple of kits in the mail... Northern Brewer Irish Red, and their smoked amber ale partial mash. I am planning to brew these one after another and repitch the same yeast.

I have 2 lbs leftover extra light English-style DME from previous brews. I wondered if it would be advisable to add a bit of that to each recipe to boost gravity a tad? I don't want to throw off the hop balance too much.

Alternatively, I could just save it and use it for a small volume brew down the line somewhere. I just don't want it sitting around forever, and 1.044 OG seems low.

Do you also have extra hops lying around to maintain the BU:GU ratio?

I have some old cascades leftover, but not the same kinds as the recipes call for. I'll probably just stick to the recipe, then brew an oddball batch with my leftovers later.