In 2012, I went to
Disneyland on Halloween (for the party) and then the 2 days after (
thanks, DIS Unplugged!). Now, I think Halloween was on a
Wednesday that year, and it
definitely was not a Friday. With that in mind, I found the party to be fine--not empty by any means, but very manageable. (If you waltz into the party expecting no crowds, the ability to see the fireworks from the castle if you try to get into the area just 15 minutes in advance, etc., you'll probably be disappointed. Plan for horrible crowds and then when it's just regular crowded, you will be pleasantly surprised.

)
Again, I expect the party to be more hectic on Halloween this year because it is a Friday, but pretty much all the parties sell out so IN THEORY it shouldn't be THAT much worse. (The one weird thing was that the parade is all about getting ready for Halloween, so listening to that at like 10:45 PM Halloween night was a little weird.

)
Thursday and Friday after Halloween were very good; traditionally, the window between Halloween and the official start of Christmas a couple weeks later isn't very crowded. Granted, Saturday and Sunday will probably be busier, but I don't THINK they would be worse than weekends any other time of year.
Now, when we went, they were filming the Christmas parade that coming Saturday--we were not in the parks that day, but I have heard the day they film the parade can be terrible for visiting Disneyland. I haven't heard a thing about when they are doing it this year, but if I had to guess, I'd think they'd do the filming the FOLLOWING Saturday this year, because they have to set up a stage in front of the castle and put up Christmas decorations on Main Street AND take down Halloween decorations on Main Street too, and I feel like doing that over the span of just one night might be too tricky. But I don't know.
(When we went, they had set up the stage by Thursday--so much for castle photos!--and there were no fireworks on Friday because of the stage directly in front of the castle. Neither was a dealbreaker for me, and again, I'm not sure either will happen during your dates anyway.)
Happy early birthday!
