What I want to know is how did Cyclops actually think that the kid was his? Did Lois run to him the very second Superman left? Do Kryptonian babies take longer to develop in the womb? Does Superman have super sperm that swim around for close to a year?
As for the kid and his powers, he's young and hasn't fully developed them yet. The piano push was one of those "mom's in danger, must save her" instinct moments. Yeah, the sinking boat is a similar situation, but remember that there's krytonite all around him.