I think so too and I don't have any blue birds currently so she'd be a nice addition. I'm thinking a blue marans, since Ideal doesn't offer many blue feather legged birds.
I think your BCM is a pullet along with the rest, from what I've seen the cockerels get huge combs quite early. @wrathsfarm may have some better insight
Back story: I had a broody, didn't want to risk cockerels, so ordered 8 Blue Stars (blue sex links) from Ideal. They say the parentage is blue Andalusian and barred rock. Received the chicks all healthy, but there were 10, two with slightly feathered legs, on the outside of the leg, pink foot...
I used the dip method, mix it in a 5-gallon bucket and dip each bird, moving the feathers around to ensure skin penetration. In my experience, it's a one and done, no need for a repeat application.
How do you know they were overheated? I live in Central Texas, so we've got the heat and humidity, my ladies can get hot, they pant, raise their wings away from their body and just lay in the cool dirt and do a lot of nothing until it cools down. As far as the pans of water go, they aren't...
Candled the BCM marans eggs tonight, tossed 7 of them, zero development, 3 more I think are quitters but I'll leave them in until my next candling 😞, the other 4 look on point.