The default groups are guest, user, moderator, global moderator, administrator. I used the term "ordinary user" to mean user.
There is only one calendar permission in site permissions, and that is "Can create new calendar events" which as noted is zero for both users and guests.
Only one island has viewing permissions possible, and that is the Shout Box. There is a Shout Box on the referenced site, and you correctly could not see it.
