If you’re using Lightroom to publish galleries, then you need to use Lightroom to make updates. If you want to change an album’s template, do it in Lightroom.
Backlight has a one-directional relationship with Lightroom. There is no way that you can make changes in Backlight, and have those changes reflected in Lightroom. Lightroom has no “listening” mechanism by which Backlight can tell it things.
The only thing you can do is make choices in Lightroom, then send them to Backlight.
You can have Backlight take over control of an album from Lightroom, but then there really is no going back. You cannot have Lightroom take over control of an album from Backlight.