1. The MPC meetings are open to the membership, but it's rare than more than two or three people show up. "Of interest to 'civilians'" is subjective. The discussion is typically over the work the committee needs to be doing, but note that this sort of meeting is where the resolutions about eligibility were made, with no notice and no discussion outside of the committee.
2A. The Business Meetings have been known to use their entire three hour slot. Whether they will actually do so is variable. I would expect the Preliminary Business Meeting to last around two hours (with the rest of the time eaten up by the inevitable ad hoc committees formed during the PBM to hash out final wording having their meetings. I expect the Main Business Meeting on Friday to use nearly all of its three hours. The Saturday Site Selection Business Meeting may last less than an hour because if the Main Meeting manages to dispose of all the business on the agenda, all the Saturday meeting has to do is receive the site selection results and conduct Question Time for future bids. I don't expect a Sunday Business Meeting; we haven't held a fourth meeting since 1992.
2B. The reason the MPC meeting on Sunday is scheduled against the Business Meeting is that there hasn't been a last-day Business Meeting since 1992 and we only schedule the fourth meeting (Worldcon day 5) as an emergency overflow in case there's so much material on the agenda that we're unable to finish on Worldcon days 3 and 4. We're more likely to have full three-hour sessions on the previous days as people really don't want to have to use the last-day meeting on account of so many people are leaving that day — sometimes that morning. The MPC can't hold its meeting until all of the Business Meetings are over. They often meet right after the final Business Meeting, which means they sometimes hold their meeting on Worldcon Day 4 and not on the final day. But the nominal schedule is based on worst-case outcomes.
2C. The more typical short meeting on Worldcon day 4 for Site Selection is why we schedule the informal Worldcon Chairs Photo Shoot for about 11 AM at the same place as the Business Meeting. So many Worldcon chairs are apt to be at the Business Meeting anyway, as well as the people most interested in photographing them, that it's logistically easier to get them assembled there, and we usually anticipate a relatively short, pro-forma session. (Amazing meetings like we had at Westercon this year are highly unusual.)
3. Candidates rarely get announced that far in advance. Nominations are made at the Worldcon Day 2 (Thursday this year) Business Meeting, and election a Day 3 (Friday this year). Candidates sometimes (but rarely) make statements. I made a statement on my own behalf last year in Australia and was criticized for "politicizing" the process, which I find an absurd criticism, because of course it's a political process. There was a long run of years where nobody was really interested in serving on the MPC and the MPC didn't do anything at all, much to the detriment of Worldcon in my opinion. I intend to give a speech at Friday's meeting in support of selected candidates.
Yes, I know that committing to a potential nine hours of Worldcon time is a big deal, especially if you've been up late at night partying. But not showing up leaves the field to the others, and leaves the decisions to those people who do show up. There are no representatives, proxy votes, or anything like that. It'd direct democracy in action. Moreover, more than one first-time attendee has come to me after their first meeting and told me how surprised they were at how unexpectedly entertaining the debate can be.
Re: Many questions, sorry....
2A. The Business Meetings have been known to use their entire three hour slot. Whether they will actually do so is variable. I would expect the Preliminary Business Meeting to last around two hours (with the rest of the time eaten up by the inevitable ad hoc committees formed during the PBM to hash out final wording having their meetings. I expect the Main Business Meeting on Friday to use nearly all of its three hours. The Saturday Site Selection Business Meeting may last less than an hour because if the Main Meeting manages to dispose of all the business on the agenda, all the Saturday meeting has to do is receive the site selection results and conduct Question Time for future bids. I don't expect a Sunday Business Meeting; we haven't held a fourth meeting since 1992.
2B. The reason the MPC meeting on Sunday is scheduled against the Business Meeting is that there hasn't been a last-day Business Meeting since 1992 and we only schedule the fourth meeting (Worldcon day 5) as an emergency overflow in case there's so much material on the agenda that we're unable to finish on Worldcon days 3 and 4. We're more likely to have full three-hour sessions on the previous days as people really don't want to have to use the last-day meeting on account of so many people are leaving that day — sometimes that morning. The MPC can't hold its meeting until all of the Business Meetings are over. They often meet right after the final Business Meeting, which means they sometimes hold their meeting on Worldcon Day 4 and not on the final day. But the nominal schedule is based on worst-case outcomes.
2C. The more typical short meeting on Worldcon day 4 for Site Selection is why we schedule the informal Worldcon Chairs Photo Shoot for about 11 AM at the same place as the Business Meeting. So many Worldcon chairs are apt to be at the Business Meeting anyway, as well as the people most interested in photographing them, that it's logistically easier to get them assembled there, and we usually anticipate a relatively short, pro-forma session. (Amazing meetings like we had at Westercon this year are highly unusual.)
3. Candidates rarely get announced that far in advance. Nominations are made at the Worldcon Day 2 (Thursday this year) Business Meeting, and election a Day 3 (Friday this year). Candidates sometimes (but rarely) make statements. I made a statement on my own behalf last year in Australia and was criticized for "politicizing" the process, which I find an absurd criticism, because of course it's a political process. There was a long run of years where nobody was really interested in serving on the MPC and the MPC didn't do anything at all, much to the detriment of Worldcon in my opinion. I intend to give a speech at Friday's meeting in support of selected candidates.
Yes, I know that committing to a potential nine hours of Worldcon time is a big deal, especially if you've been up late at night partying. But not showing up leaves the field to the others, and leaves the decisions to those people who do show up. There are no representatives, proxy votes, or anything like that. It'd direct democracy in action. Moreover, more than one first-time attendee has come to me after their first meeting and told me how surprised they were at how unexpectedly entertaining the debate can be.