Final answer:
Mary Musgrove significantly contributed to the development of the Georgia colony by acting as an intermediary between the Native Americans and European settlers, aiding in the peaceful establishment of Savannah.
Step-by-step explanation:
Mary Musgrove was most influential in the development of the Georgia colony by serving as a key intermediary between Native Americans and the European settlers. She played a significant role in the negotiations and communication as lead mediator, which was crucial for the establishment of peaceful and cooperative relations. Musgrove's efforts were instrumental in the foundation of Savannah in 1733 after successful negotiations with local Native American tribes, notably the Creek. Her ability to navigate and bridge the cultural and linguistic divides between the two groups greatly facilitated the development and survival of the Georgia colony.