Shared elements work as far as I know. But you can only have one calendar since activesync is only supporting one. This might change in future versions.
My calendar is syncing fine using SmartFolders (a zimbrabackend setting).
As far as I know they should work but I didn't try it out.
Tags are not synchronized, at least not in my setup.
Colors? Are you talking about the calendar colors? No they are not synchronized but that's not a big deal
If you want confirmation you should try it out for yourself. There are quite a few configuration possibilities you can play with until it fits your needs..