Hidan no Aria/WMG

Jossed. Aria's mother is the leader of EU
The leader of EU beat Vlad, so he or she should be really strong. Aria is considered a failed Holmes because of her lack of a partner, so the rest of the Holmes family should be incredibly strong. Kana wanted to kill Aria to stop something. Perhaps Kana wanted to stop her because she was trying to release her mother. While her mother's charges are mostly fake, there could still be real charges in there. So, EU leader => strong => Holmes => Aria's mother.

Riko is Lupin III's daughter
Because it's too damn obvious a crossover NOT to be true.