Yotsuba& is only a manga. Its relation to Azumanga Daioh is just that it shares an author, Kiyohiko Azuma. The two mangas might take place in the same universe but that's just fan theories. There's a few uncomfortable scenes in Yotsuba& with Fuuka, involving Jumbo, from what I've read so far (~1.5 volumes)

Nichijou doesn't have anything uncomfortable that I can remember.