1. I welcome them. In fact, I want my members to move the plot along themselves, rather than the staff doing it through events. Of course, there's a fine balance between the two, as giving members full control could potentially change more than what you as staff want for the site, and controlling every plot change with an event can give you a lot more work than you need.

If there's major changes to the plot, like world destruction or killing a major canon character, I'd prefer it if the members gave me a heads up, but from experience, most members are mature and considerate when it comes to these things, and you could always state in the rules or guidelines that major plot elements should be discussed with staff if you're unsure how lenient you want to be.

2. Pre-established relationships between canon characters have both upsides - and downsides. On one hand, the canon characters can immediately jump into threads and plots, because there's already someone their character know, without having to go through the process of figuring out who their canon character would know, but on the other, to some, it might feel a little restrictive?

I'd say it comes down to how much the pre-established relationship is detailed. Does it come with a long history of two people fighting alongside each other, having spent years out in the field, have they had a prior or current romantic relationship? Or is it more open for each person to decide for themselves? Like you mentioned, Character Alpha is captain of the knights, and received their training from Character Beta - this leaves a lot of room for the two players to mutually agree on the two character's relationships. Do they hate each other? Do they respect each other? Perhaps they never really got along as friends, but their fighting chemistry was great?

3. I'd either make the character a staff run NPC, or open the position back up again, stating the character's past history, personality or other important factors one would need to know in order to play a character whose presence are widely known. Maybe it would be beneficial for the plot to kill the character off, or say that they had to leave their position? I don't think there's a right or wrong answer here and I'd just go with my guts at the time, tbh.

How do you handle huge site changes brought by the plots of the members?
i mean, it really depends on what it is. i don't really structure the sites to be super plotted usually, so like. imo i just don't go out of my way to acknowledge anything in a thread or an individual plot arc as hard site canon. maybe it's a bit cynical, but in my opinion all characters are equally important to the site plot (since imo, you're not going to have a feasible team rocket if all you have is giovanni) and to a certain extent, prioritizing one small group of characters and their story really neglects all of the other stories that want to be told.

that being said though, there have been more than a few scenarios where i've envisioned a site being one way and then as time went on and we gained members, we realized it really didn't fit the established vision anymore (ie, when we opened ideal world, it was originally a superhero registration plotline site, but as time went on, we realized that most members didn't really actually care for the plotline and were ignoring it in threads). so what we do is rework the site lore and push through an update - we're transparent about it and apologize for any inconvenience it may cause, but at the end of the day, by moving more efficiently towards actually catering to what we are rather than what we intended to be, we're being more honest about it and

What are your thoughts about a site with lots of site canons that already have a "basic" form of pre-established relationships? e.g. Character Alpha is Captain of the Knights that received training from Character Beta.
i mean i don't really care? i'm not really a fan of hard adoptables but like. i guess the bigger issue i have with this is more when it's obligating people to thread with characters they may not want to since like. i'd be annoyed if i had to thread two brothers together when i didn't like the other player but i'd also be annoyed if i couldn't thread them together, if that makes sense?

essentially it's a way to do it but i just. think it's messy tbeh. but i guess no messier than doing any other canons on other sites since like. taking robin away from batman isn't gonna end well for anyone. it's just generally more easily swallowed if you're on a canon site than an original one, i suppose.

What do you do if a person claimed someone important (e.g. a King) and left the site- in situation wherein this person already made significant changes.
shrug and move on? it happens? imo there's nothing to really do about it and as much as it sucks, it's a fact of life. it's actually why i don't like huge important site canon lists - because people ghost or get busy or otherwise leave and i'd rather not get fussed over being unable to replace them. i prefer having sites where it's more of a "if we have this character, great; if not, that's okay too, we don't need them" attitude.

i know some sites do adoptables, but this always sat poorly with me since just. different people are going to have different takes on a character, and personally, i'd rather be playing my own character rather than more or less replacing a character that someone left vacant. i might not want to change much - whether it's through relationships with others or just flat out the character interpretations - but i'd still rather have the chance to actually forge something different than be bound to words or deeds that i didn't do and that i may not see my character doing. it's a peeve.

I don't have any admin experience, but these questions are still ones I've thought about. I think they're pretty good questions myself! I can't answer the first question with any authority in that regard, but:

2. As an rper, I find canon positions generally restricting and a source of anxiety for me, because of your question #3. I do like the idea of occupation/position claims, however, or I saw an rp once that called their canons "sub-plots": in other words, they were ideas for characters left out for members to potentially pick up, but they weren't essential to the site or set in stone in any way.

3. I feel like a lot of rps I've been on still don't know how to effectively deal with this. When I played on LJ/DW pan-fandoms for a little bit, the issue of inactive canons could be dealt with easily. The character would simply "go back to their world," and for whatever reason due to the mysterious nature of the panfandom world, if someone else picked them up again that character would lose any previous-rp memories, letting the new mun start from a blank slate. (It was also a cool plot device for other characters with history to realize that, no, their best friend does not remember becoming best friends with them.)

Of course, that kind of tactic doesn't work for a lot of roleplays, especially the real-life/non-fantasy ones. Still, I think a lot of rps could use a by-line that says "if you quit/drop a character, please provide a reason for your character leaving the ic world, or else we will come up with one for you." I'd imagine these staff-designated ones are typically "character x moved out of the town suddenly." I think with site canons, staff could have even more freedom to decide what these are, and maybe even come up with some interesting concepts as a result! A mun ghosted, thus leaving the captain of the guards in an inactivity limbo? Whoops, the captain of the guards died and someone new has to step up to the plate! Or, the captain of the guards vanished and now the whole squadron is wondering if he was kidnapped! Etc.