Wouldn’t be hard to power your router from the power bank too, if your already thinking of powering the sync module and the camera. Some routers are 5V anyway, so simple, but even if not, you could soon get a DC/DC converter, to provide 12V. Just be sure to check the router specs, and size it accordingly.
EDIT: You would have to consider carefully the current rating of the 5V output ports on the power bank, if you had to step up, and the router has a high peak power demand. Still it could be possible, depending on your router, especially if it is a 5V one.