Maybe they said it in the story, or maybe it was explained before. Maybe I missed it.
So, 'what are the girl's favorite food' (drinks are NOT included)
I see Shizune to be fond of something 'quick and filling', something that does the job when called for. So I was actually thinking ramen would be her favorite food considering how quick it is to prepare and filling it can be. Not to mention, ramen stalls and shops are common out there, and then there are instant ramen too. If it isn't that, I say yakisoba would be something she'd go for. Quick and filling.
I can somehow see Misha to be fond of sweets--parfait, maybe. I think that was explained in the story if I remember correctly. Outside of it, I'm guessing yakitori would be a more preferable choice--that, or unagidon (grilled eel over rice).
Lilly would go for tea biscuits or scones.
Not really, but looking at her character I say she'd prefer something classy--her dinner in her arc also hinted as much. If I were to make a guess, she'd go for a fine French cuisine or a wine-n-dine set; even then, I still can't pin-point any possible favorite dish for her (add to the fact I never had any fine-dining experience).
...now that I think about it, she'd qualify for your 'high-maintenance girlfriend' too...
Hanako is also quite difficult to pinpoint. Maybe she told Hisao about it in her arc--and I missed it--or I just find it hard to pinpoint it for her. Her fondness towards something mostly came from her memories, so if her parents decided to eat chicken liver or cow brains, then that will be her favorite food (not saying it is). So, I'm not sure...I can see Hanako as an 'autumn girl' though, so bake yams is something I can imagine to be in her liking. Maybe Bacon.
that, or chocolate
Rin would go for curry. I don't know why, but I just see 'curry' as her favorite food. It's flavorful, full of colorful spices and is actually simple to make--just like how she is. Maybe seeing her eating curry the first time in the story influenced my decision, but who knows. I'd go for curry.
Emi. Lemon soda, Lemon cake, lemon rolls. No, seriously, I can see her liking sweets--although if I remember correctly, I think she said she prefer spicy food? Not sure about her to be honest aside from sweets.
