This is prettymuch my line of thinking, with the potential addition of Team Eden, ready to work out how to invert the process they used for revitalising the Empty.
With the possibility that MSQ will also lead to creating a new bridge between worlds – whether purely between Source and First or some kind of free travel between dimensions – that also gives us the means to help Zero directly connect up with the others: from the Thirteenth through the Atomos portal to Source, then this theoretical new travel method to First, if more direct travel is not available – and vice versa to get the others into the Void more easily than the two-person voidgate spell they were using before.
Or perhaps it is simpler for the team from the First to tunnel into the Thirteenth and meet with Zero that way. Though on the other hand, that means Taynor and Unukalhai are tied up with the spell, and also physical distance may still apply – it's not much good tunnelling into void-Lakeland/Mor Dhona if Zero is over in void-Thavnair.
