What are the chances that a kitten born would have a DIFFERENT genotype than the sister's cat Moo?

A kitten born will have genotype different from sister because the concentration of gene expressed is different in all kittens as it is a phenomenon of codominance.

Explanation:

The moo cat is black and white bicolour cat.

The cat has white colour fur which is combined with some other colour as black.

White colour in cat has white spotting gene that prevents the patches over cat's body.

SS genotype results in large concentration of white colour.

Ss results in medium concentration of white colour.

ss results in black or other dark colurs with very meager or no white colour on skin.

The resultant colour appearance of skin in cats is due to codominance. The colour of the skin depends on the concentration of gene and protein expressed. So, the sister moo cats can have diffrent genotype and different level of white colour patches on the skin and genotype of SS,Ss or ss can be there in sister kittens.

sorry, but you do not have posted the diagram.