Here's the thing, Benoit Blanc could solve most Scooby mysteries and the Scooby gang could solve all the knives out films, but I think only the Scooby's could solve the Kira Case
L could solve the mysteries in Knives Out but I don't think he could catch a Scooby monster
The reason Benoit Blanc can't solve the Kira Case is simple, he's too famous. The moment he takes it on, and possibly before he does, light already knows his legal name and face and can kill him
The average Scooby monster doesn't feel interesting or complex enough for L, so he wouldn't try to solve the case. But he would care in Knives Out due to the complexity of the crimes, but would probably on second thought fail to solve the case as he wouldn't care enough about the people whose lives are affected by the crime
Blanc would care about the monsters in Scooby and work to solve them, this much I think is obvious, he just has to meet one person and he'll be hooked
The Scooby gang, while less talented than the other 2 have less fame, giving them cover from light and making him underestimate them, leading to them being able to solve the Kira Case. Velma could solve Knives Out 1 on her own
Basically, this is the order of ability to solve mysteries of these 3
Mystery Inc is the only one who I think could solve the others cases
Blanc could solve Scooby cases but would fail at Death Note
L couldn't even solve the Kira Case
I would add Columbo into the mix
Like Blanc he would care enough about the monsters to solve a Scooby case
I think with his persistence with cases and his attention to detail would enable him to solve any of the knives out mysterys
The Kira case is where he would really shine. He's completely unknown and I believe we never learn his first name thus keeping him safe from Kira. More importantly he uses his suspects arrogance against them, a trap that Kira would certainly fall into. Kira would certainly grossly underestimate him, while he collects the details that he needs to get Kira to confess
I do think that all the other detectives would be able to solve his cases, although L much like with the Scooby cases would not attempt to solve Columbo's
I do think Blanc would have fun with a Columbo Case or two























