I have bantam Cochins and my birds average 5 eggs per week. We don't use any artificial lighting and our egg season starts in February and lasts through the beginning of September.
They handle the cold quite well, but heat is not their cup of tea. Big fluffy feathers, feathered feet, and small combs make for poor heat exchange. Ours can handle the Texas heat fairly well though as long as they have plenty of fresh water and shade. I keep a spot of loose soil damp in their run on really hot days so that they can dig down in the dirt for a cool dust bath, and they seem to like that. You can expect a drop in egg production during a summer heat wave.
Cochins are generally friendly birds and make nice pets. I have encountered very few obnoxious roosters in the breed, and in my experience temperament seems to be a highly heritable trait.