Generally speaking, cosmetic changes are very low priority in terms of research, especially for things that can be adjusted freely in-game. The process of someone documenting which relevant save blocks need to be adjusted would be no different from a PKHeX developer doing it and any other user doing it, so it is left up to whoever feels the most driven to do the research. DLC is already over a year old, proving this is very low priority.
You should be comparing save files before and after the relevant style cards have been received to reduce the number of changes, making it easier to pinpoint where and how the data is stored.