It’s either an in-joke or an irony that the not-terribly-terrifying villain of “A Babysitter’s Guide to Monster Hunting” is named The Grand Guignol, for Rachel Talalay’s perky, clean-cut kiddie-horror steers as far clear as possible of the macabre gore and gruesomeness implied by the name. In this tale of an underground babysitter syndicate dedicated to fighting the things that go bump in the night, even the monsters are cute: roly-poly, crayon-colored, off-brand uglydolls that look like Mike Wazowski’s less genetically blessed relatives. Yet cuteness supplants genuine charm in this Netflix-released adaptation of screenwriter Joe Ballarini’s YA book series, which may adequately distract very young ones on a socially distanced Halloween night, but offers ample room for improvement in the franchise it seeks to start.