Do bantam cochins make good pets... in a word, yes. Especially the hens, though the roosters can be back-pocket type boys too.
While some breeds are more 'expected' to be better pets than others, such as cochins and silkies, I am a strong believer that any breed can make an excellent pet if handled often and gently from day one. Some of my flightiest birds in general currently are Egyptian Fayoumis, but I have 2 roosters and a senior hen that insist on being my "helpers" at all times. They come running over to my feet from anywhere in their yards, eat from my hand, don't mind being picked up and stroked - all the while the rest of their breed keep their distance, run off, make a big stink if I have to catch them, etc. Just depends on how hands-on I was with their raising.
Some of my best pets, and some past house birds, were Cochins. They are curious, calm and very easy going as a breed goes.
Another option for friendly pet-like birds would be Silkies. I've got two house silkies sitting near me right now, actually. A three-year old buff hen that knows her name, comes running when I call and wears a diaper and dress, and a young blue cockerel that is being raised as a house roo.