The chick starter does not have the calcium in it that laying hens need. As soon as the girls start laying you need to switch them to a layer or all flock feed. Those will provide the added nutrients that your girls need. You should also have a dish of oyster shell or some other form of calcium...
Chickens are very social animals and most breeds do fine together. I live in Florida and have Barred Rocks, RIR, Marans, CCL's, Araucanas, Orpingtons, SIlkies, Seramas and Tolbunts. All of them do fine in this hot, humid weather. I just make sure they have fresh water available at all times and...
I have over 15 roosters in my flock and all of them get along just fine. Yes, there is an occasional squabble but I have one roo who is King of the yard and he makes sure things don't progress to far
A picture would help. The light color you are describing sounds as if you have a roo. The barring is thinner in males and sometimes looks to be greyish. You could also have a blue barred rock which would make for the greyish appearance.
The barring is another give away on male/female. The hens (like in this picture) have wider barring than the roos. The other pic looks to be a boy with the narrower barring and red comb.
Pullet.. The comb and wattles are too small to be a boy. The lack of pointy hackle and saddle feathers is also another good indication of not being a boy.