Oh boy, I really feel for you. Sounds like you really love your quails.
I had 2 ladies in with my 1 boy, it was peace & harmony for a while, then he started driving them crazy, and they were scrambling to escape him. I did seperate them, ( I only have 2 girls old enough to be mated ) he was very miserable. So much so, that he is now in my freezer.
Moving forward.. this is my suggestions..
You could try putting some lanolin, or vaseline on the back of the hens neck each day, to give her some peace?
Is there any way the 2 pens you have could be joined together? If not, just stick with the biggest one.
Can you give them some dirt or sand? Just in a bowl, or container (you can get it from garden or wherever). They love love love bathing in it.
If you could maybe get some branches or sticks? Some things to provide hidey places in their little house? Small cardboard boxes, old pots etc. That'd help make them happier.
If you have any bits of fruit (they love apple), or leafy veggies like spinach or lettuce, peg it on the cage so they can peck at it. They really enjoy it.
Hope that helps! Good luck, and I hope his little lump heals.