Good points. There is definitely some spot-on language in the letters. That said my stake has largely decided against local unit (ward) control and decision making, instead having stake-wide policies determined by their understanding of the Area Presidency's instructions. So what the instructions from the First Presidency letters of the 11th and 25th actually mean is only determined based on the subsequent instructions from the Area Presidency. Basically, we read the letters from the First Presidency, but can't act on them directly.
We simply cancelled stake conference rather than simply omit the in person component and continue with the broadcasting that we normally do, because they thought we weren't allowed to conduct stake conference remotely. My understanding is that there was a clear carve out for having remote/virtual stake conference where it could be done without significant expense to the members, but I was not a recipient of the original stake conference related instructions, so I could certainly be wrong. As far I as know, there isn't a cost for using the church's webcast system, which is what we've always used in the past. Maybe satellite uplink time is super expensive and they didn't want to consider any other technology. That said, I would have that that would have already been included in the budget since we always do it for stake conference.
I think it a hybrid system with Zoom Webinar can be done fairly easily, requiring checks well before sacrament meeting begins of course, and would likely work well. I'm not sure if the stake has considered having high councilors speak in this manner since our stake is going back to full length sacrament meetings, but this might be a very good approach for that. At this point. I'm planning on trying to magnify my calling once the stake's back is turned.
