Sure, horror movies might be stronger around Halloween, but you have to remember that the price of the moviestock is already taking that into consideration ever since the release date was announced. So you can't really say a horror movie will be increasing price just because it's halloween season.
As for their starbonds, remember they adjust 4 weeks after the release. So if you're not ready to hold on to them for that long, you might be better off without them. At least until you have a clear sense of its adjust. You have to be sure you understand about starbond adjust before investing. There are a few tools available to help you on this: Kaigee, The HSX Dude, among others. You can check them out here.
Horror movies with no release date and no news are not good investment oportunities even if it is Halloween.