He could also be doing it in a sneaky way. Maybe next time he see's Jon (which would probably be many, many years in the thinking of that moment: spend the next 10-20 years as Hand of the King) he will tell him about his "aunt" and not reveal that it is his mother. He probably thinks he will never see Jon again in fact.
As far as I remember, doesn't Lem speak like with a low-born, smallfolk dialect? Of course this could just be a cover but wouldn't a squire for the crown prince speak like he spent time in the capital?
I like the idea of just getting someone who is physically correct for the role. I think that's all you need. The Mountain should be an easy role to play. There isn't a whole lot of nuance. Grunts, yells, screams. I think the big guy can pull it off.
Well the person with the dragonclass cache might have been trying to hid/hold onto the horn so the Others didn't get it. Not that he would use it himself, but having it in his possession is better than the alternative.
Qyburn is a tool of Cersei's at the moment and can't survive long once he "master" is gone. That being said he is smart enough to attach himself to those who can get him places. He was smart enough to find service and surve with the Brave Companions, I think that bodes well for his ability to survive post-Cersei. He may retain his position if he can quickly switch his allegiance and provide useful services.
A popular opinion is the Green Grace as she has sufficient access to the nobels of Meereen and enough clout to organize them. The harpy is a "woman" so it makes sense that it would be her thematically. I hope it is not the Shavepate, I really like him.
It really seems silly for them to split it. I don't think they have enough programming for both channels. Are they going to complete with themselves fro the 9-10pm slot this season with another show? I think that only encourages DVRing...I'm sure they know more about this than I do.