Jefferson as a Greyjoy - the Greyjoy’s are an interesting House, in that they not only have blood of the Andals and the First Men, but also their own unique blood because they are descends of the natives that lived on the Iron Islands separate from the mainland. I think that fits Jefferson fairly well, who is at turns FTL + Wonderlandian + Storybrooke, a man who has all parts. More than that the Greyjoys live in a way that directly opposes the traditional way of life on the Westerosi mainland. Basically, they do what they want, and that is very Jefferson to me, as a portal jumper and then later choosing not to be so he can raise Grace. Basically, he does whatever he wants. And then there’s the “pay the iron price” business, which means that what they want they take. Again, that just screams Jefferson to me.
Rumpelstiltskin as a Bolton I’ve seen a lot of people saying that Rumpel is more of a Lannister because “a Lannister always pays his debt” BUT that is simply only one facet of a Lannister. The Lannister also put a lot of emphasis on family name, family title, and prestige and showmanship—which is just not Rumpel at all. Rumpel is a very behind-the-scenes sort of man, whereas a Lannister wants their efforts to be known and to be rewarded (Tywin wrapping the bodies of Elia Martell and her children in Lannister red). House Bolton seems more in line with them, whereas they are a house of repute but most people don’t care for them because of their hobbies. Read: flaying (which is like the Dark One, everyone knows him but everyone fears him), and the Boltons are very behind-the-scenes too, playing their cards close to the vest. They supported Robb Stark, but only until he started losing the war, and they jumped ship to save their own skin, and also to get what they wanted—the North. Rumpel is basically doing the same thing, playing Regina and Charming and even Emma when he needs to ULTIMATELY get what he wants (Baelfire). The only other house I COULD see Rumpel in is maybe House Baelish, but only because Rumpel = Littlefinger for OUAT, but honestly we don’t know enough about House Baelish as a whole to say that Petyr Baelish reflects the actual house, or if he’s a fluke that does what he wants, so Bolton seems the safest choice for Rumpel imo.