It's a tiny change and it serves a very sensible purpose. It confuses some audiences to have two characters with the same name. Since the kid's nickname is Robin (Sweetrobin) in the book, it's really not a big deal.
McCormack may be dark, but the personality he's giving off isn't Bronn at all. You've got to look beyond the coloring. Bronn is a laughing, social sort of killer.
Straight female opinion: Jerome Flynn is a handsome older man, and he looks like he could be a wiseass. He may be somewhat older than Bronn appeared to be in the books, but who cares? He's a minor character, and his age isn't important to any plot point. Being American, I'm not familiar with Robson and Jerome, but their youtube clips are hilarious. Looking forward to seeing what Flynn does with Bronn.
There's no character need for Lysa to be fat, and let's face it, how often do they cast fat women in big roles in American television shows? I mean, it's being made in Europe but this is for HBO.
Jamie is the same as Jaime. It really really does not matter.
Several of the guesses fit extremely well. West, not so much.
People are trying so hard to cram Dominic West into small roles he'd never play. If we're going to be that absurd, let's just cast him as Moon Boy and have done with it.
The golden rose is the sigil of House Tyrell. Given the mention of the hollies and oaks, it's pretty clearly a reference to Loras Tyrell (Finn Jones), who was on Hollyoaks.
Winstone does look older than he is, but Glenn looks his age, definitely not 40 with that weathered skin. I think this one is simply too big a stretch. Winstone would be great for other parts.
This has been discussed. Winstone is four years older than Iain Glenn, Mormont's son. Extremely unlikely to be him, since Lord Mormont has to be about seventy years old or even older.