It looks like you're building the blockchain and connection system from scratch for this project. It'd save you a lot of time to use something that's already available and build the tools you want on top of it.
A similar project is Scuttlebutt which is a peer to peer social network. You can easily change the secret handshake key to something random to create your own network separate just for this project. This seems very similar to what you're building and has been ongoing for 5+ years so most of the hard problems you're solving are already solved. They also have a Go client if you're a big fan of Go.
There's also Gun which is a decentralized database. I haven't used this as much but it could be another good alternative.