Tunarr: Create and configure live TV channels from media on your servers

Dumb question, but is every channel "synched" such that, if two different users tune in on Jellyfin, at separate times, they will still see the same thing at (roughly, given latency, et al) the same time?

I was not able to figure this out from the docs thus far.

By default, yes. There is an option when creating a "channel" to make it on-demand too.

Yes, client connections are synced. They also all reuse the same underlying transcode stream, so there is no extra work with more connections (besides delivering the stream)