There might be an issue in those save files that breaks the customization for Britney. Not that she really matters at this point. Anyways, the outfit files in 'resources' folder have changed a bit in 26.1 so here's an update. Again, one save at the end of current content and the other in the beginning.
Save files go to "My Documents\SeasideMystery" and the files in the "resources" folder go to "{game folder}\Seaside Mystery_Data\resources".
Some events in game will reset some unlocks. IIRC when you unlock Janice's customization in the story, they unlock as if there were no save edits done. Basically you would need to re-edit the save to unlock all her options again. It also resets all her outfits back to defaults, which kind of sucks. Can't remember if this happened with anyone else.