Wow this is really challenging for anyone that is not already on slack
We tried two approaches, slack-connect from the Stanford slack inviting other labs, and a fresh workspace
The fresh workspace required money to enable calls, otherwise it was just a chat
The slack-connect required slack admin approvals from each participant's organization
Eventually we got everyone connected through a call once each organization approved, and we also ended up having to create another workspace which we connected to the slack-connect channel then invited a member of the team to, so they could access the slack-connect call.
All in all it took 0.5hr and a clever workaround to get everyone connected. It is not clear how to invite guests from outside the organization without administrative approval to a call.
One plus for this is the nature of a channel call appearing in a particular channel, with current participants listed, for channel members to join as they like.
Emotes seem to be nearly at par with Zoom, sans hand raise, speed up, yes/no indicators.
MS Teams channel calls ping everyone in the channel. Imagine SLAC general (Slack, 1.2k members) getting buzzed XD
Simultaneous video and screen sharing not possible in a channel call
Scheduled meetings not possible with Slack (not really what they aimed for in the first place)