I think that you can do the inverse, instead of starting to do your edits in SOP and then start working in LOPs, start working in LOPs by loading your USD (with a sublayer or reference node) and make the edits inside of a SOP modify LOP.
If you want to continue starting in SOPs, you can export your edits, and then in LOPs load the original asset and then load your edits layer, it will override without changing the rest of the data (the materials and assignments) if you don't change your path and usd attributes of course.