No, there was more Coulson backstory in S1 and S2. We know born in Wisconsin, his dad died when he was a kid and then his mom died some time after, also he was recruited right out of early college by Fury.

Yes! The "conglomerate owner's child struggling to prove themselves to their father over the official heir" is def a Korean movie/tv trope. I've seen so many chaebol (rich society) corporate machination stories that I could fill the sea with them.