Sorry, Internet went crazy last night.
My Goofy photo is 5 minutes after first parade start time, so it looks like I remember wrong and the meet does run throughout the parade, just without Mickey.
Mr Knight... he's a tough one. One clue for him showing up in the past was the amount of fog in the area - high fog meant his appearance was close. But if you can't judge the fog level that so doesn't help you. You can try asking a CM, but they are not always very helpful because Avengers Campus is supposed to be a "working Campus". So they often don't like to give out times and/or locations.
Sandersons: this is from last year and 2022, I have no confirmed info what they are doing this year. My personal experience from last year: it was pot luck. Last time I tried there was some sort of unofficial line that had formed at the left one of the "entry/exit points" because that is where they had let in in the past. Some CMs clearly were not happy, and promptly the other point (which was used as an exit later) was opened to walk in people about 30 minutes before event start. Other nights CMs did not allow people to line up at all, and there was a mass lingering in the area basically. It wasn't pretty, pretty much like the Peter Pan bulls run with strollers and all that.
I am going 9/17. Not sure if anyone is going before me, but I am making a list of questions open before I leave and will try to find out what I can. Please note I am not going to be running around to check when every treat trail opens and stuff like that. But things like "is Mr Knight on some sort of schedule or was that appearance a fluke?", "who comes out first at the Fountain, I want Pain and Panic!" or trying to get length of meet lines into some sort of order I will happily cover.