The Hoare

If you can't survive a 10-years winter, you wouldn't be able to do anything. Dead people can't fight

One could argue that the Martells are the most powerful, since they know how to kill dragons

Full stop. In our world winters are short and predictable, in Planetos they're not.

House Stark. Grey wolf in a white field? I bet there's a lot confusion in the battlefield. Flowers make sense. Flowers were used by the french royalty. Frankly, it's better than nobles obsessing over the animals in their coat of arms.

Agriculture isn't only about cold.

How would you do that with winters that can last years? It shouldn't be possible at all to stage a large scale invasion of anything.

There are hundred of options better than a second son. The North itself is full of young heirs whose father's would eagerly accept a marriage with their liege lord's daughter.

They raid Essos, of course, the Red Kraken gained his nickname while raiding the Stepstones. I suspect that they use their ships for trade as well. We know that Asha's ship Black Wind traded all over the western coast of Westeros, and likely on the east too. Yes, but Westeros would need a stronger monarchy, which isn't going to happen in the next hundred years. It's not a hostile practice for anyone in Westeros.

Second sons are not fit for someone with Sansa's status. Besides, the gift does not belong to Winterfell, but to the Night's Watch. I suppose that if war broke out they would be forced to stay neutral

Tyrion. Samwell would let his lands be ravaged by stronger men, just like Tytos did in the Westerlands.

He looks like a ugly monkey and he's a depraved dwarf. I doubt anyone would ever accept Tyrion as the lord of Casterly Rock. He simply doesn't have enough support to hold it.

And yet Robert was still the king, and he clearly considered it a kidnap. If this was true she would've brought Tyrion to King's Landing, and not to her sister in the Vale. If it's the King's justice she that she wants, why not bring him to the king?

They couldn't win a war agains't the Westerlands on their own, and it was Catelyn that broke the King's Peace in the first place. Only the king can grant lands

I don't think any of them has enough power to destroy the Freys.

I've always supposed that he would be closer to Renly. In terms of kinship it's the most likely