That last boy has a tail, I think he's just slow growing the feathers. They'll be lovely come spring, I'll bet.
Silver is dominant over red/gold, so that could influence which bird you keep. Do you like silver or gold birds better?
I like beards and muffs, so I'd pick the bird with the nicer ones. A nice tight pea comb is linked to the blue egg gene, so I'd be going for that as well, to increase my chances of colored egg laying offspring. Otherwise, around here it's all about how nice you are and then how pretty you are. If you aren't nice, to me or the ladies, it's off with your head. And it doesn't matter how nice you are, if you're skanky to look at, off with your head.