I could be very wrong (and hopefully someone will correct me if I am), but I don't
think that any SoCal schools (either in L.A. or in Orange County, around DLR) are out on any kind of break in
late October. I
think that most of the breaks are over a bit earlier in the month. However, anytime I think I've got it narrowed down to a week or two with no school breaks of any kind so I can answer someone's question on the subject, someone else will pop up and say "There's a break in the such-and-such school district" during that time!
It seems that breaks in all of the California-adjacent states (and even the non-adjacent states) factor into the crowd levels as well.
Still, though, I think that most of the big breaks that would draw lots of people from any school in any state to the parks are over by mid-October, or slightly thereafter. And, coincidentally (or maybe not so coincidentally!), It's a Small World goes down for its holiday overlay right after that time, like over the next to last weekend of October.
Prior to last year's Halloween Time season, there were characters in Halloween costumes out and about on Main Street at random times of the day -- Skeleton Goofy, Pumpkin Donald, etc. Jack Skellington and Sally were out for photos near Haunted Mansion Holiday. Also, the Villains had a regular photo spot in Fantasyland, and there were usually 3 Villains there at the same time. Then, at the actual Halloween party there were more characters set up in various spots around the park, some in Halloween costumes and some just in their regular gear (like Buzz Lightyear, for example). Jack Sparrow, Captain Hook and Peter Pan would be set up in front of the Rivers of America, by the Mark Twain. That sort of thing.
Before the actual Halloween party moved to Disneyland, there also used to be a Villains photo spot in DCA, in the Hollywood section of the park. This was also when DCA was involved in Halloween Time, and you'd hear themed music as you passed under the Golden Gate Bridge. Then there was Candy Corn Acres, which was really cute. Even the CALIFORNIA letters in front of DCA were candy corn-colored at one point! At that time, like in 2007-2008-2009, both parks felt as though they were part of Halloween Time. Ever since the DCA construction kicked into high gear, Halloween Time has been but a mere memory in DCA.
This year, with the new
Monsters, Inc. movie on the scene, it would be great if DLR could somehow do a Monster-themed tie-in to the Halloween season in DCA, and add in some extra little decorations around the Mike and Sulley ride. I've always, always thought that they didn't do enough with the Monsters for Halloween Time anyway, but this year would be a perfect opportunity to work the Monster angle and bring Halloween back to DCA (last year's Frankenweenie stuff didn't really do the job, I don't think).
Anyway, back to my point -- as we all know, as of last year, the character dynamic changed, and the Villains suddenly became more "exclusive." The Villains photo spot was gone, so all that was left was the "meet one Villain at a time" thing at the Carnival/Round-Up, and the rest of the Villains were out in full force at the parties. Also, the costume-clad characters like Skeleton Goofy and crew were no longer on Main Street, greeting guests. There were some characters back at the Carnival in the daytime, but again, more of them were at the party. I think Jack and Sally were out at non-party times as well.
I'll be very, very interested to read your assessments of the DLR holiday season vs. WDW's grand holiday/Christmas festivities. Some WDW holiday vets have gone to DLR for the holidays and come back very disappointed because there "wasn't as much" there as what they were used to at WDW, while other WDW holiday vets have come back from DLR holiday trips and said that they loved DLR's holiday celebration and couldn't wait to go back!
As for Halloween Time, I feel that there could be much more to it and many more ways Disney could build on it in different lands, if they wanted to shell out the cash. The Halloween decor is not anywhere near the level of immersion and thoroughness as the Christmas/holiday decor,
but the interesting thing is that I have read some reviews of DLR's Halloween decor from WDW Halloween vets and most people seemed to agree that DLR wins in the Halloween decor department. The only thing that WDW seemed to have the clear edge on was the
Boo to You parade, by most accounts. Our little mini-parade/Cavalcade is apparently a pale shadow of
Boo to You, but our Halloween Screams fireworks are awesome!
So I sit and wait
Is it time, yet? 
The dates are not going to change that dramatically (which is why it's pretty easy to figure out when they will be each year). They don't have a whole lot of leeway to change them that dramatically.
That never gets released this early in the year (especially not at the same time as the Halloween dates), although we can usually guess what the holiday date will be! DLR is really making an effort to follow WDW's lead, I guess, in releasing dates early on!
