For future litters.....
Before the kits are available for everyone, ask the other person involved in the pairing(Whoever didn't design the kits) if they want a kit and let them pick before the others are available for adoption.

That way it's fair to the other person if they want a kit or want a certain one.

I've seen this used on other sites and thought it would be good to have here too.

I'm not going to enforce it unless you all want it to be an official rule, but I'd love it if you all did this. Especially if you have the litter ready when the other person isn't around.