Lots of vegan options.
Yes they have a few vegan options.
They definitely have a vegetable broth that they can use in all their soups. Udon done right is just flour, salt and water. The vegetable udon is very good. It's what my wife had and she is vegan. As far as sushi goes, there are only a few ways to do it with the normal ingredients to make it vegan. Which i am sure they would do to accommodate you. I am not sure they have a specific vegan section on the menu, but I'm sure you are used to finding the vegan by default options and ordering to make it vegan. I have found most Japanese places to be very accommodating.
I think they do--with avo, cucumber, nori and sesame seeds. Don't know what it's called.
Thanks! Your answer is awaiting moderation.