What about following other players and seeing how they play? Do you guys simply look at a list of players, "teleport to (character)", "follow (character)", and then get some popcorn and watch, taking down notes?
There's a command we can use, with arguments, called "monitor" that lets us watch what you input to the game and what you see. We can do a full-blown monitor (and many of us do, for those in our clans), or we can narrow it down to, say, only magick. Something I like to do is monitor all the players in my clans, and then monitor everyone's use of magick, psionics, and rogue talents to keep up on who's doing what.
And are imms around 24 hours, especially off-peak?
I can't promise there's someone on literally every waking moment of the MUD, no, but I can say that generally, yep - I haven't logged in, even off-peak, to an empty house.
Was there a lot of history related to animating someone's beetle?
No, it was a pick-up-and-go sort of thing. Unless someone's been around for a while and has developed a bond with their mount, or has a mount that's particularly special, nothing really needs to be done for trivial animations like that.
Are some of those NPCs really formerly stored characters?
Not every stored PC becomes an NPC and not every NPC is a stored PC, but yes, it occasionally happens.
Are say, the Bynners hanging around the Gaj only allowed for animation by the T'zai Byn, or the Kadian merchant in the Bazaar only animated by those in charge of House Kadius?
On things this trivial, not really. However, the line is a bit sketchy, and one must be careful not to overstep their bounds. Animating a certain animal that holds significance to a clan may not be kosher with that clan's staff, for example. Animating higher-ranking NPCs in any clan, I usually only do with explicit permission for a reason.