Please get information from the Japanese embassy of your country of residence. General information is here.
Yes, if you need a visa. We do not support you except an acceptance letter.
Tokyo has two international airports: Haneda and Narita. The conference venue is about 1-1.5 hours from each airport.
Tokyo in August is hot and humid, although most buildings have air conditioning. Rain protection may help you.
You can use eduroam if your institution joins the consortium. Otherwise, UTokyoGuest is available.
University cafeterias will be available. There are many food options around the campus, too.