I went to one of the universities you mentioned
I would have to say though, why go to Kansai Gaidai and pick up Kansai-ben when you can immerse yourself in standard Japanese in Tokyo...
Tokyo Gaidai can be an alternative if you prefer public schools.
ICU and Sophia have very good Japanese courses because they not only accept Exchange students, but a large part of their regular students grew up overseas etc and do not have very strong japanese skills.
Waseda, Keio and Ritsumeikan are all great schools, and no doubt have good language programs but their main target seems to be the Japanese students. Of course they are international too, but not as international as ICU and Sophia, maybe.
Location wise, if you want to enjoy Tokyo without commuting for hours on a train, stick to Sophia, Keio, Waseda and Ritsumeikan.
Waseda and Sophia central tokyo, Keio can be different depending on the campus, ritsumeikan, I forgot where they are...
ICU and Tokyo Gaidai is on the fringe on Tokyo, and not very convinient...