Thank you for the exact time stamps of the photos! I have been wondering about this. Likely this has been mentioned and I missed it as these threads have been moving quickly, but:
The SnapChat was taken at 2:07 PM, which means the picture of BG was taken at 2:30 PM. Being such a clear and exact time -- i.e. 'on the half hour' -- indicates that a meet-up with an established agreed-upon time is seeming more likely. BG was on time, Libby and Abby were early.
I agree, 23 minutes is a longish time to wait on a high bridge.