Which c2 constellation should I get?

I am looking into getting either c2 lauma, c2 nilou, and/or c2 nahida for a nilou bloom team. I am completely fine with spending but I am wondering which is more important than the other?

I already have Nilou's sig, and Nahida + Kokomi are on a full EM build with sacrificial. I already heard that R1 Lauma isn't a huge increase (~10% or so) which I'm okay with getting the 6.0 event weapon for her.