A - Almost certainly Mr. Potter (Interesting note: He was rescued from Potter Valley, it said. That was one of the locations of fires here the year before. I imagine that they got him as a fire survivor.) was outside when the fire flashed through, or had access to the outdoors through something like a cat door.
That means that cats who had no access were, sadly, trapped.
B - He may have been loose all of those days, and living on the food that was kindly put out by others. I love that people are doing that.
Or, someone may have taken him in, and he recently got outside and went home. I wonder that because no one claims to have seen him before this.
Either way, I know that they are happy to know that his fate wasn't what they feared, and to have him back!
Love All Life, Thank You For Posting! :)