For the outline pumpkin it’s OK to use high contrast yarn. I think the Fall Banner will look better with solid-fill patterns than outlines, but this Pumpkin Outline might be useful for other purposes.
The Pumpkin Outline is a more natural pumpkin shape, not uniform from side to side.
Pumpkin Outline — Right Stem
Sample — L1-3: RHS “Tangerine,” L4: YBSS “Olive”