Fidasx Yes I'd obviously add a boolean, but the point is, recreate objects doesn't let you filter which instances are regenerated, it just regenerates them all.
the instance bank does look promising though, I'll look into it.
EDIT: Just looked into Instance bank, doesn't work because it requires loading all saved objects, not objects by region.
I looked into Grid Freezer too but it seems to be weirdly complicated, performance intensive, and doesn't preserve Z order.