"Go talk to them vs him"...is this definitive as to how FD does it or guess work.
Nobody has published a paper yet on the ED peer-to-peer moment to moment gameplay, but a number of us have been analysing the network traffic and verbose logs since Alpha, and there's a consensus that this is how it is. But here's a thought experiment: Given the types of cheats that have been observed (and fixed), is there an authoritative instance host, or is authority devolved across peers?
It would seem like a lot of unnecessary overhead if FD transmitted all clients in an instance to the peer joining vs just saying "Talk to this guy, he'll tell you about his peers".
Efficiency and reliability are in opposition, and in the connectivity jungle that is the internet, reliability comes first.
The peer to peer topology provides robust multiplayer that in the case of failures, gracefully degrades to single player without interrupting gameplay. Because it's symmetric, it has the desirable properties of simplicity (no need to select an instance host and ensure that their connection is able to support that) and reliability (because if any connection between two peers fails, they just don't see each other, and if a peer leaves the session, the other peers take over authority for its objects).
I do feel like we could keep coming up with more technical issues regarding this but technical issues are just issues that need to be solved.
Of course - I'm not trying to put obstacles in your way, just pointing out that basing ideas on a 'instance leader' model will be different to how ED's networking works.