This is just my experience, but we had a day old cuckoo marans that grew up to be the son of satan! He was huge and very mean not only to humans, but to his ladies as well! After trying for several days to "calm" him a bit, he ended up in the freezer. Good luck with whatever you decide.
I'm not so much worried about the hens. It is the roosters that I prefer friendly. Learned my lesson the hard way which is why I like the orpington breed so much. I already have them though but would like to have another breed in separate pens.
We have a Birchen Marans and he is AMAZING! So gentle with people, he loves getting scratched and petted, not to mention how beautiful and proud he is strutting around the farm! Highly recommend. We had an Old English Game roo and he was the devil. So aggressive. Our guy now is such a wonderful change.
Roosters are a toss up on each individual. Some within a breed will be mean and aggressive and others will be sweet as can be. Get the breed of roo you want and go from there. You can get two or three so that you can choose the best roo for you. My advice is to not cuddle the roo when he is a baby. Leave him alone and let him be a chicken so he doesn't bond with you. When a roo is of breeding age he will want to be top rooster, and if he sees you as another chicken he will want to fight with you to ensure breeding rights in the flock. I've had many roosters over the years and haven't been attacked once. I make sure roos know who and what they are.
If you want a friendly rooster, either buy one that's already reached maturity and has shown his colors or get several and the choose the nicest one to keep. There's no such thing as a "friendly breed" but I do believe that buying from a breeder who culls mean roosters improves your chances.