Don’t worry too much about what will happen in a year or so. You can make changes at the NVC stage and even delay the process to work out where everyone is physically located.
Another potential option is direct consular filing (DCF) of the I130 with exceptional circumstances. If you have proof of a pending repatriation back to the US, you can request the consulate in Japan process the I130 which is much faster. I am no expert on that process, but what I do know is if you file the I130 with USCIS either online or by mail, DCF is no longer an option, so I would spend time researching that first.
Here is a thread that may be helpful, and is fairly current.
