That would be possible but would complicate things quite a bit.
There might be some other ways to set this up to avoid the problem.
The ogonek anchor is usually in a different spot so it makes sense to use a dedicated anchor like it is done already. There should be only a few places where it might be at the same spot as the bottom. And in this cases, it might be possible to just move it 10 units to the side to keep the anchor from overlapping.
The cedilla on the other hand is usually at the same position as the bottom anchor. For the few places where it is different, it could be done with an alternate bottom anchor (e.g. bottom_cedilla). So the cedillacomb has a _bottom anchor and the base glyphs that needs a different position for it, gets a bottom_cedilla.
The issue with that solution is that as far as I know, this only works if you create a dedicated /glyph_cedilla glyph that you then compose in a ccmp feature. While slightly cumbersome, changing /cedillacomb from using _bottom to using _cedilla appears to be the better solution.