I went to DL this past October (if you want to check out my tr it's in my sig) during, almost exactly, those dates. There is a special Halloween Party called Mickey's Trick or Treat Party (MToTP) at DCA on some nights. It's like $25-30 I think. We didn't do it because it wasn't worth the money for us, but I know a lot of people enjoy it. You get the whole DCA park and the rides, as well as a bunch of trick-or-treat candy stations and plenty of opportunities to meet characters. However, tickets sell out on many nights, so if it's something that interests you, I recommend buying them well in advance.
As for ride refurbs, yeah there will most likely be some rides down because it's not a super busy season. The only times that rides are not down (unless they are under an extended multi-month refurb) are summer and Christmas basically, sometimes Spring Break.
Just another thing, crowds were definitely there when we went because many AZ and
UT schools have "Fall break", and there was also a big convention when we went, so if you're expecting walk-ons, think again. Not to say that it will be jam packed, but you might need to plan a bit more for crowds than during other "low season" times.