Best and easiest chicken to keep as a pet?

When you first get the chicks they will need a heated brooder area for about 4 weeks. After they have their feathers they can be removed from the heat. Housing doesn't need to be complicated as long as they can get out of the weather. Of the breeds you listed I know from experience buff orpingtons are easier to keep than black links and ameraucana. Partridge rocks are said to be an easy breed to keep. I can't say anything about cochins or cresteds. Black links and partridge rocks are the most productive layers of the breeds you listed. Bantams are mostly kept for amusement as living lawn ornaments. There are so many breeds of bantams that there is no universal answer to how easy they are to keep. For a lot of good information you should get the book Storey's Guide to Raising Poultry.