I like the idea of introducing a different kind of multi, and it's a thing I feel Arcen should continue to innovate on. The current idea isn't super interesting to me, essentially it sounds like creating a gift exchange, but it's a start in a potentially clever direction.
One way you might word this is that your player character has limited contact with alternative dimensions, and you can reach through to other parallel realities to exchange information and certain kinds of goods or resources. That sort of narrative also leaves room for variances in time.
I have no idea what TLF's gameplay is going to be like, but what if, in a battle, or on the main planning screen, you could siphon off some resources or battle help from someone else?
Or, what if you use some extra resources you have laying around to build a part of a giant space laser that you have no use for, but would be a real help to another dude?
Anyway, the whole "We all tend our gardens and meet at the market place" thing is certainly novel and I'd like to see it branch off further from it being a simple goods exchange.
Maybe even another (fairly simple) gameplay layer, like combining your forces to combat a trans-dimensional warlord that's been dogging both players' progress. That 'war' wouldn't necessarily be something you work together on in real time, but something that hums along in the background. Like, each positive trade results in an increase of entropy counter or something, and after a bit you have to both commit a certain amount of time/skill/resources to beating that down to avoid the effects of entropy on both universes. Those effects might be wormholes, interdimensional pirate attacks, spectral gremlins in the ship workings, etc.
And other horrible ideas.