Khelil Kridi comments

not 100% true and for the trash bin I think it is better practice to keep it on yourself. in most countries where trash bins are installed, the bin gets full very quickly and the trash get on the floor. please don't forget that Japan is a country where there is many crows "trash bin Party"

as for the allergens you can ask for content of food in pretty much all restaurants. But let me remind you that most of Japanese food is really basic. let's take sushi it has rice and fish -> and rice is cooked in a very basic way. if you are allergic to rice then don't eat it. for other western restaurant they all have a detailed list of ingredients, you can ask it anytime.

signs in stations are so obvious that you just keep following simple arrows. the problem is the the way the information is formated in the signs is a little different from other countries. You have to learn how to use them it takes 30 minutes at most (if you have a good mental structure)

In Japan smoking in the streets is not common, there is special areas for that no smoking signs are everywhere in most restaurants and cafes. If you go to Izakaya then it is absolutely normal to see many people smoking because those places are made for smoking and drinking. Don't go to Izakaya if you don't like smoke and noise.

Usually Japanese waiter is not responsible of what is in the dish. It is better to have him ask the chef then let him improvise an answer. don't be in a hurry your safety first.

I am tired to write