As TEAMS is live now and fully functioning, I was expecting the "Add external contacts" is available now for E3 license but it isn't. I still cannot find the "contacts" option in CHATS or TEAMS window. However, when I use the "Add member" and typed an external SFB account email it says "We didn't find any matches".
I made sure that "allow external contacts" is enabled by admin.
Somehow, in the Settings, under the Privacy>Manage Priority Access option, I can add external contacts. I guess that's a bug? That's confusing, isn't it?
Those are two different things you are trying to do. One is guest access which has a big long checklist of items to turn on. The other is external access, which takes time to propagate and you also need to be set Teams only to use.