While it may seem odd to see Fred Jones depicted as a moron who believes aliens to be behind everything (not to mention the Running Gag of accusing Red Herring of the crime regardless of the evidence) and Daphne depicted as overly concerned with looking fashionable when they acted more intelligent and mature in other continuities, it makes sense when you remember that this is a Spin-Off Babies adaptation. The show is about Scooby and the gang solving mysteries when they were children, and the way we acted when we were children isn't always going to be how we act as teenagers or adults. It's highly probable that Fred has cut back on the crazy conspiracy theories and Daphne has toned down complaining about other people's wardrobe or her clothes getting ruined in the continuities where they are adolescents or adults because they've matured past behaving that way.
As a certain fanfic pointed out, Red Herring probably would come to resent Fred both for all those times he falsely accused him of various crimes, which probably didn't help his adult reputation, and for eventually becoming a fairly respected detective. And the scenario presented, someone angry at the gang going after Velma, is disturbingly plausible...