As near as I can figure it out, pumpkin seems to be a synonym for yellow belly. Crossing a pastel yellow belly champagne with a jigsaw involves 5 gene pairs.

The pastel pumpkin champagne:
Gene pair 1: a pastel mutant gene and a normal gene
Gene pair 2: a yellow belly mutant gene and a normal gene
Gene pair 3: a champagne mutant gene and a normal gene
Gene pair 4: 2 normal genes
Gene pair 5: 2 normal genes

The jigsaw:
Gene pair 1: 2 normal genes
Gene pair 2: 2 normal genes
Gene pair 3: 2 normal genes
Gene pair 4: a mojave mutant gene and a normal gene
Gene pair 5: a pinstripe mutant gene and a normal gene

Results (probability is 1/32 for each):
normal
pastel
yellow belly
champagne
pastel yellow belly
pastel champagne
yellow belly champagne
pastel yellow belly champagne
mojave
mojave pastel
mojave yellow belly
mojave champagne
mojave pastel yellow belly
mojave pastel champagne
mojave yellow belly champagne
mojave pastel yellow belly champagne
pinstripe
pinstripe pastel
pinstripe yellow belly
pinstripe champagne
pinstripe pastel yellow belly
pinstripe pastel champagne
pinstripe yellow belly champagne
pinstripe pastel yellow belly champagne
mojave pinstripe mojave pinstripe
mojave pinstripe pastel
mojave pinstripe yellow belly
mojave pinstripe champagne
mojave pinstripe pastel yellow belly
mojave pinstripe pastel champagne
mojave pinstripe yellow belly champagne
mojave pinstripe pastel yellow belly champagne

No super mojaves or ivories from this cross.