They are beautiful. I can't say much about whether it's normal or not. My Teddy Bear Sunflowers didn't make it at all.

They all look pretty to me, the third one look kind of strange, but I guess bees will appreciate it.

Thanks for your comments garden friends. I think I have found an explanation to this strange behavior. A little googling confirmed my suspicion that just like marigolds the sunflowers too are composite flowers. Composite flowers are combination of many florets having different petal shapes. The florets are divided mainly in two groups, disk flowers (very tiny petals) in the center and ray flowers (much bigger petals) surrounding the center, which in combination give sunflower (or other composite flowers) it's final look. As they are all individual flowers, seeds collected from different zones will result in different shape of flowers (I remember reading this somewhere many years ago though in context of marigold).

I am assuming the teddy bear sunflower has very low number of disc flowers as compared to Ray flowers which is why they look so full and fuzzy. But in my seed packet atleas one viable seed of disc flower was there which I happened to germinate and grow. And that explains the strange looking flower on plant 3, it's comprised only of disk flowers. I'm still not sure seed from which part results in a daisy like flower as on plant 4. But atleast now I have explanation behind the different appearances :)

the seed companies should be more careful in collecting seeds from composite flowers I guess.