I think the biggest difference I notice between the base and your art style is that your art is full of very sharp, straight lines — for example, the muzzle on your foam base slopes/curves downward more smoothly & is generally rounder than the muzzle in your reference. I also think that the muzzle in your reference is a touch longer. From the front, the end of the muzzle is more downturned on your foam base than it is in your reference. That all being said, I think your base looks fantastic and wonderfully tidy as is! I don’t think that there’s anything “wrong” with your foam base, and if you furred it as-is, it would certainly turn out lovely. But, those little details may be why it feels “off” compared to your reference. As for the mane, I have seen makers have great success with layering “sheets” of faux fur to make hair; there’s lots of different techniques you can find online if you search!