The more I think about the more convinced I am that it's going to Junior that dies in these batch of 8 episodes. The foreshadowing is there for it, I'll explain in a few
It won't be Sky, too obvious.
Mike would be my other pick but for some reason I don't think it's going to be him.
Jesse is too important to die right now
Hank, hasn't been that involved so far plus in some way I see him and Jesse being heavily involved with Walt's last stand.
Lydia and Marie, wouldn't generate enough interest.
Why it will be Walt Jr. The foreshadowing is there. Walt JR will die speeding ot trying to do donuts. A lot of Walt is doing is ego driven to finally prove he is the man. Its obvious he has always been jealous of the respect JR has for Hank. The buying of the cars and bragging of speeding and doing donuts and how JR can't drive like his father was him trying to get JR's respect. His ego couldn't take his son respceting Hank over him. But while Hank had his sons respect, Walt was JR's hero and JR will die trying to emulate his father. Walt JR won't be able to control the car because flashback to earlier in the season, his legs don't work like ours. When Sky said Walt is the danger it wasn't meant to be his life of crime wouldn't come to kill the family, it was his ego that will kill the family. Walt's ego is the danger.
That's just my theory
I've been neutral about Walt Jr. So far but if the season happens to end that way that would just be depressing.