Hi Kirbyboii69,
Akeno the neko will want different food at certain points in your relationship. If you can't give her the sundae maybe she feels like eating something else.
Kuroka the succubus is an incomplete story line so far. Checkl your journal to see the available relationship level with the girls currently in the game.
The journal also has a Game Completion percentage to let you know if you have completed all available content.
Kind regards,
iLEWD