Otherwise known as my theory that Expartiette is, in fact, a member of the Parsons clan.
Here is what I believe we know:
1. Citizen Dawn, Expat's mom, has an almost religious belief that superhumans are superior to non-powered humans.
2. The first child born to the Parsons family in each generation has the powers of the previous generation plus one new power. Additional children born into the family do not seem to have powers, though I'm not certain if any Legacy has actually has a known sibling.
3. Expatriette was born without powers. This did not please her mom.
4. It has been stated that we have already "met" Expat's dad.
My theory: Citizen Dawn decided to procreate at some point. Considering her beliefs, it isn't difficult to imagine her subscribing to a eugenics viewpoint of creating children. What better father for her child than a Legacy, the second most powerful (from her point of view) superhuman on the planet? Legacy's genetics plus Dawn's genetics should create the perfect superhuman child.
I'm not suggesting that any Legacy cheated on his spouse to father a child. Instead, I believe Dawn got hold of genetic material and used that, plus a bit of comic book super science, to impregnate herself. Given that Expat was born powerless, it stands to reason that she would be the second child of her generation and not the first.
Given that Pauline, the future Legacy, is only 18 around the start of Sentinels I think it is reasonable to assume that Expatriette was created using Greatest Generation Legacy's DNA and not the current Legacy's. In other words, I believe Expatriette is Paul Parsons' little sister and Pauline's aunt.
Christopher recently told us that some Legacies have had siblings.
I can't recall where I read this, but I thought Dawn killed Expatriette's father (sometimes called Citizen Dusk). Whether this was from Christopher, or just forum speculation, I don't know.
Neither do I. However, I do know it was stated that Citizen Dawn killed Expatriette's father for not giving her a daughter with super powers. Considering we also know Greatest Legacy was killed by Baron Blade, this theory doesn't seem likely.
I don't think we've been told about meeting Expat's father in the card art. He was supposed to be in Citizen Dawn's deck originally but that got removed in original play twisting apparently.
There is also the ongoing theory that Expatriette actually does have powers but doesn't realise it - people have suggested that she has some kind of uber survivability but attributes this to her super-strong flak jacket whose card, after all, has no upper limit on the amount of damage it can protect her from...
We've been told Expat's dad was a Citizen of the Sun which removes Ambuscade as an option since he inherently doesn't have any powers and didn't gain any until we started into the SotM timeline. That's also why I would say the Legacy theory doesn't work because Legacy being a Citizen isn't even an item Christopher alludes to. The theory is great but just doesn't line up.
I remember asking Christopher way back in the old forums about Expat's father, and he did say that Dawn killed him for not giving her a child with powers. So he is most definitely dead.
If she did kill Dawn's dad that blows it out of the water.