Would I have a problem with food if I have shellfish allergy and didn’t plan to try raw food?

Hi, I plan to travel to Japan next year (probably around Osaka and the places nearby it). My concern is I have shellfish allergy so I would have to avoid a lot of the food such as takoyaki and okonomiyaki. Are there any common food that I should avoid as well? If I didn't dare to eat raw food, would it be a huge problem to find food during the vacation? I did not want to go eat fast food as it would be miserable.

Secondly, are there sufficient dustbins near the streets because I didn't want to litter or carry rubbish around while holidaying. I can pack them all in one bag of course.