Hmm.. The "light greyish color" could either be blue (the dilute of black) or agouti... If the hairs are banded (have darker / lighter areas on each hair) then it is agouti. If they are a solid grey, then the color is called "blue". The patterns I am not very good at, but I think if the pup is mostly solid but with white feet / belly, then it is a "berkshire". If the pup has a lot of white with a colored heat / shoulders / stripe or spots down the back it is called "hooded", although to be a good hooded pattern it should have a stripe down the back that attaches to the hood.

Goodl uck with them, they look great! I have pet rats right now and am still on the fence about breeding them to start a feeder colony.. I'm thinking I'd have a hard time feeding off the pups.