I agree for the most part, except that I do think 3c will appear to grow up when short and I'm not sure how wetting that hair would make 4a coils looks like curls.
My hair is like Mahogany curls and when it's short it's like this:
And when it's long it's like this:
If it curls when wet it's curly and more 3c and should dry curly assuming you don't manipulate it. IMO water doesn't create curls where they aren't, it makes your hair go back to it's original state before you either combed/played with it into frizz, slept on it, etc. I can play with my hair until it's just a puff...but I'm a terrible terrible curly
. I consider it 3c because my curl pattern is a lot larger than a coil. Albeit tighter than most or mixed 3cs.