Is C0 Chevreuse viable?

Hello! I'm going to pull for Varesa and I'm wondering if she needs C6 Iansan and C6 Chevreuse to be playable. As of now, I don't have Chevreuse and I'm hoping to at least get a one copy of her and knowing the 4-star system, it is hard to get them C6. Also, I only have C4 Iansan so I also hope I got her at C6 too. Does she needs it really bad? I have Mavuika and those two would complete the Overload team