A Quokka Dreeds its Weird

I read all of my dad's old kids books and the books my mom remembered from her childhood and could find at a thrift store - so, like, the original Tom Swifts, the Hardy Boys, Nancy Drew, the Bobbsey Twins, etc - and the only one I remember that's not on your list is the Happy Hollisters. The Happy Hollisters were a family of pretty young crime-solving kids (and puppy and kittens). IIRC they were less likely to encounter pirates and drug-smugglers than the Bobbsey Twins; the ones I remember were more family drama mysteries.