I really don't understand a number of things here.
Quorum disks plural? An MS cluster has one quorum disk.
What is a 2x1 cluster?
Does 'two active and one passive node' mean you'll have a three node cluster with two virtual servers on it?
Nothing says you can't use the quorum disk as a normal cluster resource; the quorum stuff can be out of the way in a subdirectory and doesn't take much space. I have been unable to find an MS doc that says this is a bad idea. Which means I haven't looked hard enough. It does not strike me as a good idea particularly.
Normally, I'd dedicate a disk to the quorum and set up a quorum group and separate Exchange groups with their own disks. They can be different LUNs on the same array if you like, we do that, it works and I have been unable to find MS best practices on cluster disk layouts anyway.
But I'm not sure if this is an answer to your question, not sure if you're asking the right question and quite sure I don't fully understand your question anyway.