Hello there,
There are some quests that get visually stuck, this is corrected for the next version. Do have in mind is only visual, you can still complete the quest.
Getting Kat hooked doesn't need to be done instantly, but it does need to be done before arresting Mario, otherwise it cannot be done. As to how, you just need to go to the terrace and once there keep talking to her by using the chat bubble until the event happens, you need to do it with her 3 time for her to get hooked.
There is a chance the save got corrupted, or it could get messed up if you used any kind of modifications. Does the load issue happens when loading from inside the game, at the main menu, or both?
There is no real plans for bimbofication, Anna's comment is a flavor text as doing reference to the "bimbo" kind of woman, but no plans to actually make it happen to one of the girls. Btw Dreamy does go through changes and surgeries, but is not really a bimbofication.