Hi, I'm a bit confused at how to lose.
"The goal, the hope, is that at the end of the year,
after 12 messages have been sent and received, the two
parties will agree to meet."
This goal is not written on just one of the players, but on both.
It seems like both players should just give coordinates in their introductions to immediately win?
None of the 6 objectives of the Sender seem to conflict with the objectives of the Receiver, which means they can always be trusted. The Sender's writing prompt also suggests that they always have resources ("absolutely"), but "need people".
My criticism is that this seems to be more of a seed for a series of collaborative writing prompts than a game that can be lost.