Well the bad news about the multiplayer walkthrough is that I never actually got around to writing it. The differences between multiplayer and singleplayer are so minor that I never really felt the desire to sit down and write a tutorial that would either
1) Be incomplete
2) Be mostly a re-hash of what I'd explained in the singleplayer tutorial.
The good news on the other hand is that
1) You can find the missions from the 3rd party forum
here.
2) As I said above, multiplayer and singleplayer are very similar. In fact simple singleplayer missions can be turned into multiplayer missions simply by going to the Mission Specs editor and selecting multiplayer rather than single player. All you then need to do is to select the player's wing and use the Player Start option from the Ships Editor. After selecting up to 12 ships as player ships (In TvT up to 8) you're pretty much done.
Something with the complexity of the main Diaspora campaign would require a lot more effort but simple missions can be converted and it's not hard to build your own missions.
I can't think of any way to share your keyboard layout off the top of my head other than simply giving them a copy of your pilot (from diaspora/data/players/multi/inferno) and having them simply clone it to create theirs.
If you have any other questions, we're all happy to help.