One obvious reference to TDKR was when Supes reaches out his hand to get the Sunlight, when he temporarily gets knocked out after destroying the World Engine over the Indian Ocean.
I don't think I even know what TDKR scene you're talking about. Unless the shot of Bruce staring at the TV in Bane's prison all sad?
Oh ha, I thought you meant Dark Knight Rises. I guess that could be a reference, if there was a sunflower or any flower in the scene I would definitely agree, but there could be several images of Superman reaching out for the sun to get back into a fight in the comics so hmm, who knows?
I don't know if I'd call it/or if it was meant as an easter egg
but, seeing young Clark playing around in the backyard wearing a red cape, an posing like a super hero
got me thinking... who is he emulating?
(not saying it meant that any real heroes existed then)
but, what fictional heroes did he grow up reading about it comics, or watching on TV,...
it just opens up the idea that the concept of cape heroes existed
I think I have the answer for you: Clark wasn't emulating anybody. He just grabbed a red sheet and ran around playing with his dog. In turn, he created by accident the superhero concept, which by coincidence, later in his life when he found out about his origins, he would wear a suit with a red cape just like what he wore at this age. And yes, Kryptonians were a caped culture, but given what this movie was suggesting, and rightfully so, that Clark invented the concept and Superman is the first (until we find out more about the sequel) superhero, just like the real world where he is the first, that's what I got from that flashback.