First of all, I did not test the code, I just went over the changes.
About the code, there are two mistakes:
homonomy_list_getter in common_accessors is only used once. This is fine, but the way I imagined it is that if this kind of functionality is only used once, than implement it inside the class (this time its EditHomonymy). Then later if needed to avoid code duplication refactor stuff out of the class and in common_accessors. But that is fairly subjective point and you can decide to do it another way :)
second one, if your IDE does white spaces this way, than create a big commit with only white space changes and than work from there. This is again not so important, but makes git blame and commits themselfs much less readable.
Otherwise, yes, everything looks nice and clean, gg :)