Could we work in time blocks? For example, you could say "Alright, it's now 6 AM to 9 AM.", and everything that characters would do in that time can be done. It would prevent people taking off ahead and keep everyone somewhat together with time in case interaction occurs, but also allows a good amount of flex, keeps it fairly easy. The person who's getting up at 6 sharp - or is still awake, if they're a bit of a party animal - can do their thing, but the person who gets to work at 8 can roll with that.

Posts wouldn't be all that restricted that way either as far as interaction goes, especially when a collab is involved, and people wouldn't get too ahead either time-wise even with heavy interaction.