Both systems will be entirely replaced
Use one common layout showing roof edges, valleys, gutters, outlets and discharge destinations. Have the roofer identify the flashing sequence and the gutter installer identify mounting and capture details. Compare the written scopes for overlaps and omissions before work begins. The goal is not to make one trade responsible for every component, but to make each transition and inspection responsibility clear.
Notice next: Request a joint pre-work review of the roof-edge drawing and retain the agreed version with both proposals.