I'm afraid I'm not qualified to help you work out the colour scheme of the future generations, I can vaguely recall the diagram with the black & white rats in school but that's that. You'd perhaps have to find out which is the dominant colour gene & so on.
And is it true that mutts have more puppies than purebreds? Cause everytime one of these mutts has puppies, it's always near 10 at the start, (till some start dying). Is there any good way to prevent them from dying? With the first one that died, I think the mother might have changed positions in the dog house, and hurt the little fellows neck.
I don't know whether its true they have more but it wouldn't surprise me, they're generally hardier than purebreeds. On the matter of preventing them from dying, ten seems quite a lot for one mother to feed on her own and there's bound to be competition for who gets most of the milk, is there a way for you to check the littlest pups are getting enough to eat and then supplement their diet if they seem thin? These smaller ones often end up getting sat on by their bigger siblings and sometimes don't make it. Also, perhaps you could move the whole family into somewhere they'll have more room so the chance of squashing the pups is reduced.
Its nice to see a mushy post, good luck, I hope it all goes well, enjoy your little family