You are from NZ yeah? you have posted that you would like to breed your unknowing unliniaged 'pitty' on the NZ forum. then you leave and ask here, lol.
You cannot tell what breed your dog is. In NZ we have no pure 'blue' apbts, i am going to say i am 99.9% sure that it is a x breed. with that .1% it may be a mutant dialation gene, but i highly doubt it.
Nor do we have bullies
You were told she was a jackfrost dog, and she had 6gens of liniage, but the breeder never gave it to you?
I will also add all BYB;s in NZ will use frosties name and jeeps name when selling their pups.