IMHO, it would be more trouble than it's worth, but if you can figure out a way to pres/filter/separate the remaining juice from the pomace, then have at it. If you try to ferment something that thick, the yeast won't be able to move & reach the rest of the sauce. If you try to thin it with water, it will taste watered down. If you try to thin it with more juice, all you're doing is adding sediment to the cider, which defeats the purpose. You might as well just leave the sauce out & ferment the juice.
I'd save that sauce for other things, like baking it into cookies, using it on ham/pork chops/etc...
Might work well in a home made BBQ sauce, or even in an icecream recipe. If you have a food dehydrator, you can make it into fruit leather. You can use it in many ways, but I think not in cider making.
Regards, GF.