My team is mostly in office, but we do have people in 2 other time zones. Communication happens mostly in slack (even for people in the office - because it would be too loud otherwise - open plan office, gggrr), but also to include people not in the office. I think having remote people in various time zones is fine, as long as we can "get together" once in a while. We do virtual board game night (well, afternoon for most of us) once a week, and of course, do sprint reviews and planning together.