Think of this:
- Initial alliance between Choshu and Satsuma.
- Both "restore" the Emperor and declare war on the Shogun.
- Shogun wins against alliance in the battle of Toba-Fushimi. Stalemate between "Imperial" and Shogunate forces along natural borderlines.
- Great conflict within the Imperial court. Some wish to support the Choshu-Satsuma alliance, some wish to support the Shogun.
- Shogun, thinking the Choshu-Satsuma alliance is still supported by the Empeor, declares a new Emperor, causing even more confusion.
- Within this mess, a Russian-backed Ezo rebellion allows establishment of the Kingdom of Ezo.
- Individual daimyos support either the Shogun or the Emperor. Alliances shift constantly.
- Death of several foreigners caught within the conflict prompt foreign powers, such as the US, Russia, Britain, the Netherlands and France to deploy troops in individual domains.
- Angry things did not go as planned, Choshu declares war on Satsuma. With the dissolution of his empire and foreigners taking power, Emperor Komei dies in a fit of anger.
- New emperor meiji declares neutrality from the war. His action is unseen, however, as there already are multiple self-claimed "emperors" within Japan.
....and how possible is this? I don't know. So I ask you whether it is