Hi Gisele! Thanks for bringing your question to planDisney.
Most of what you'll experience during
Halloween Time at the Disneyland Resort is autumnal decor, including Mickey Mouse pumpkins and yellow and orange bunting on Main Street, U.S.A in Disneyland Park. You'll also see some Halloween-themed Disney merchandise and treats in festive colors like orange and purple. None of this is ghoulish. If viewing kind of theming runs contrary to your beliefs, there's no good way to avoid it at Disneyland Resort this time of year, unfortunately. It is featured throughout the season rather than on specific days.
Otherwise, there are a few Attractions with Halloween-themed overlays, which you could skip. In Disneyland Park, Haunted Mansion Holiday in New Orleans Square is the only Attraction with a Halloween overlay; while Guardians of the Galaxy - Monsters After Dark in Avengers Campus and Luigi's Honkin' Haul-O-Ween and Mater's Graveyard JamBOOree in Cars Land all receive overlays in Disney California Adventure Park. The cars in Cars Land are also in costume. You might run into additional Characters dressed for the season throughout your visit. Again, these overlays and costumes are not ghoulish but playful and appropriate for all ages. It's up to you whether they fit within your family's standards, however!
You wouldn't be interested in purchasing tickets for the nighttime
Oogie Boogie Bash - a Disney Halloween Party since it features more Halloween theming and entertainment, along with lots of Guests in costume and trick-or-treating. Dates for that party haven't yet been released, but the party won't affect your park experience during the day since it is an extra-ticketed event that takes place exclusively at night. Disney California Adventure Park does close early on Oogie Boogie Bash nights, but you can either visit Disneyland Park on party days or hop over to Disneyland Park when Disney California Adventure Park closes with Park Hopper.
I hope this helps you make your decision for your upcoming visit!
Elizabeth