Now the shadow with the face of a hound does sound like the Hound, and certainly he was intimately involved with the fates of Arya and Sansa at least.
The one armoured like the sun appears at first to be Jaime. Though on reflection, there could also be Tywin. Or maybe it just refers to Lannisters in general. At any rate on current evidence there's no better interpretation than something related to that tribe. And if it's Jaime, he also has his fate bound up with Cat's daughters.
By now I'm wondering how any of this relates to Ned, since that would pretty much have to have happened in book one - I guess it's possible that 'them' in the original text referred only to his sisters, or to his family in general and not necessarily each and every one. Perhaps I'm trying to read too much into it.
The giant in armour made of stone is the most interesting. The obvious assumption is Ser Robert Strong, AKA Frankengregor. Now Ned is bones long before he appears. Arya and Sansa are both well away from King's Landing, and I can't see that he would be likely to directly affect them, though it's certainly not impossible.
But is that the only explanation? Why stone armour; the armour made for Strong was too heavy for any normal man to wear, but it was iron. Might it refer to dragons, to be waked from stone and to grow huge? Certainly to result in much blood and death, and the way things are going perhaps to spell ruin for all who seek to control them (read: all) as well as their enemies? How about Stannis' attempts to animate Dragonstone?
(Which, of course, is clearly built on a volcano that is far from extinct, and clearly isn't the only area of Westeros with volcanic activity, and the Doom of Valyria is clearly a supervolcano. All of which spells one possible ending to me.)
But for now suppose it is Strong. This shadow looms over them both. Them appearing to mean the two preceding shadows, and that really set me thinking. Now it occurred to me after I'd already jumped to a different conclusion that it could simply mean that the third shadow loomed largest, indicating that Strong is to be more important, perhaps, than the Hound or Jaime Lannister, in the Starks' fates. But suppose it's looming over them in the same way that they loom over Bran's family?
That's curious because the Hound is supposed to be dead already, and apparently confirmed by the author even if not confirmed in-universe. And neither the living nor the undead Gregor killed him. One could say I suppose that his brother's shadow loomed large over all of his life, but I struggle to think of anything that is to happen in the books (barring that we have yet to learn about what Gregor did to his little brother at the time of Bran's dream), or anything about the Robert Strong incarnation. So perhaps I am reading too much into it after all.
If, on the other hand, I'm not, we appear to have the shadow of Frankengregor looming over Jaime Lannister. Which is interesting indeed.
Strong is Qyburn's creation, supposedly made specifically to defend Cersei. Now Qyburn isn't the most trust-inspiring soul in the world - even in the world of aSoIaF - so it could be he turns on her. But frankly with Jaime and Cersei at each other's throats, loyalty from Qyburn and Monster seems at least as likely to result in Jaime facing off with her pet.
Now, Strong's primary purpose at the moment is to be Cersei's champion in trial by combat. Could Jaime possibly be his opponent? I think he's busy elsewhere, there's no compelling reason for him to be chosen (could Margaery perhaps decide he's the best of her abysmal set of options given Loras' fate?). That would give him scope to seal Cersei's fate, if he is the Valonqar of prophesy. Yet he would need to win for that, which both seems highly unlikely given Jaime's current state, and throws doubt on that interpretation of Strong's shadow looming over Jaime, unless they both kill each other, of course.
I just now, as I was finishing writing the above, had another thought about the giant in stone armour. Armour of stone? Or flesh of stone? Given all that's under it is blood. Greyscale suggests Connington, or perhaps Tyrion? I thought he'd turn out to have got away with it, but it's more than possible that he'll come down with the disease. Tyrion, fond of joking that he is a giant. Cersei's little brother. Perhaps to be the doom of both twins?