^Every canon appearance of Touhou girls.
For my predition: They would split off as first, since the tension between them is high (Lunarian and Gensokyo, The Mountain vs the general youkai and the Youkai vs Reimu). Roughly speaking, they would split into : The Yukari faction consist of Yukari's friend and surbodinate, The Lunarian faction consisted of the Lunarian girl, the lunar rabbit army and Sagume's worker , The Mountain faction consist of the Kappas and Tengus, The Heaven faction consist of Tenshi, Iku and the celestial servant, The Hell faction consist of Eiki, Komachi and Eiki's worker in her post. The Underground faction . The Scarlet Devil faction. The Alien faction. The Evangelist faction consisted of the religious leader in Gensokyo and their's surbodinate (though they themselve would consist of 4 small group and not exactly solid). The Junko faction consisted of Junko and Hecate and other indivituals that would prefer acting alone or in small group like Marisa, the mid-youkai, the fairies, etc...
Normally such a divisive in number would spell doom in general, but this would actually speed up the process instead, since they would like to avoid interfering with other in fear of M.A.D (yes, I compare them to nuke). They all going to inflicted heavy damage, but each faction would have more of the effect on certain enemies than other ( like the Yukari faction on high-level target, The Lunarian and faries on Zombies and Mutant target and so fort), though some faction would tend to not fight and building their foundation instead, like Evangelist and Mountain, and they would be the one, alongside Lunarian as a side-effect to build the civilization. In a few day, they would become a small, scattered with some highly advanced village due to the material gotten from the spoil the
"adventure" group taken and sometimes trade with each other for food and water, since edible and drinkable tend to be rare and need special processing technique only some side held. They also would need to deal with the counter-attack from the enemies and treating people with suitable medical need, but they would go strong, though some of the sector would be mile away, sometime even 10 or 100. The damage deal to the enemies would still be small, due to the need for a foundation and civilization.
A few day later, they would solve the second problem : Infrastructure. Since this would arrive from the need to trade, the Mountain will be the one to proposed it,
(To be continued)
EditLike I said, they would need to solve infrastructure next. Though I guess now it would take, at most, a week to done the basic. The Mountain would be the one to propose it, because especially in this senario, they thrive on trade and tool. But because of that, they can't do it without a proper line of trade, a "Silk Road" of the apocalysptic if you will. The reason why I said propose though, it's because they know that they cannot do this alone. They would need Manpower, Resource, Protection against the enemies. Most of these thing they could just do it with their own, but there's one thing they must negotiate: Permission for building said thing. Not just between faction of their own, but also between potential buyer, such as the survivor of this place.
So, the first one they're going to propose it is, as expected, the Yukari faction (or rather, I would even think
they would be the one who came and proposed it to them). It's because they're the one who know the cause, have the most agenda, and also they have the highest capability for negotiation (being the overlord of Gensokyo help that). With the Yukari faction, they also would have surplus of resource and manpower as well, though I guess their pride wouldn't allowed for Protection. So, with the first ever alliance being form, they would convince the other for the infrastructure and the official trading post, possibly known as "adventure and merchant guild" or as 7/11. They would successfully negotiate these faction (not nessesary in order): Evangelist, Hell, Scarlet Devil, Alien, Underground, Heaven and Junko. The last one would be the Lunarian, but they wouldn't stay isolated for long...
Because of the infrastructure building, the land they would reclaim is about that of a city now, due to possible settlement merging with them on the way. Though the damage is small, the enemies would start taking notices.
(To be continued, though you could added your own now.)
Ayayaya, If you're post is the last, then please use the edit button instead of double/multiposting -HeleIf I do what you said though, no one would be paying attention to my post.