Enabling a presenter to lock the video stream for all users who join a meeting, is planned.
Pinning participants is already available – this was tracked in https://microsoftteams.uservoice.com/forums/555103-public/suggestions/19512820
An error occurred while saving the commentAvi Newman commented
I hope the spot light also ends up in recordings. Today I pinned a video of a presenter, but the recording still only showed her on 1/4 of the screen. I know there is a work around where the you record your screenshare, but that will unfortunatley capture all the IMs I get during the recording.