Last report, SFMM is attempting to make Fright Fest still happen. The OC Register had an article, and they've been sending out surveys. It would obviously need some adjustments, but I was thinking that Aftermath is basically all outdoors already. It'd likely only take minor adjustments to make that one happen.
That said, most of the rest of their mazes are indoors, but they are exploring options. Should be interesting to see if it works out. I'm hoping for the best, but am always braced for the worst.
As for Knott's, I'm not really surprised they canceled the event, but I am a bit surprised they didn't announce or try some sort of alternative event, even if it was just a family friendly/no scareactor walk-thru, an "alone" style haunt, or something virtual. They seemed more innovative in that regard than HHN.
But yes, I am thinking there will be at least some independent events. I know it's not the same as a traditional haunt, but I still have enjoyed Arcana/Jadesintown Instagram Game, Terror DTLA Horror themed virtual escape room, and Road Trip Mysteries. I also am going to hope that ZJU and CreepLA will figure out something--I honestly think CreepLA could totally pull off some sort of "Unfriended" style Zoom experience. And there's still talk of Haunted Hayride.