"Can we come in first?"

"Sure." She steps inside. 

And in! 

Ellie follows them inside. "Do you want the short version or the long version?"

"Start with the short version."

"Short version, Ellie Potter, pleased to meet you. I'm an alternate universe timetravelling version of Lily's daughter."

Eyebrow raise. "And the long version?"

Ellie gives Fay the same summary of her life and times that Lily got.

...Interesting. Also, it definitely presents an opportunity... She'll look into the horcruxes, though it might take a while to verify things - also she's unsure how much risk in terms of 'chatting up dubious information sources' that Ellie is comfortable with. 

None of Ellie's contacts would, uh, remember her. She's confident in her ability to handle threats to her person; the main risk would be in leaking that they're aware of his horcruxes to Voldemort.

"My most dubious but also best contact is a Death Eater in the Inner Circle, actually... But I don't think she'll flip on me or let anything slip - she hasn't yet. ...And she might suspect about the horcruxes already, some of the things she's told me line up with that well."

"That does sound very dubious. I'm not personally acquainted with many Death Eaters, but my impression is that they are not generally very trustworthy."

"I can try sounding her out more subtly first..."

"I would be more comfortable if she was confirmed to be willing to flip on him entirely."

"...Hard to say. She isn't loyal, but - she really doesn't like magical Britain. Though maybe I can talk her into running away to the muggle world with me..."

"If you think that would work."

"I think it's worth a shot."

"All right," she agrees. "Up to you."

"There's also a lot of other questions on what to do... The horcruxes seem a likely priority - we'll want to also find you a place to stay - and start figuring out what other actionable intelligence you have..."

"And figure out how well my history matches yours and what the key differences are."

Fay's pretty aware of current goings on, so they can do some of that comparison now? Also compare major players, since that'll matter a lot. 

Ellie's on board with that. She can list known Death Eaters and members of the Order of the Phoenix that survived.

She has clarifying questions about a couple of people - especially Andromeda, Narcissa, and Bellatrix. 

Andromeda Black was married to a muggleborn and had disowned her family. As far as Ellie knows, she stayed out of the fight. Narcissa married Lucius Malfoy, but was more practical than ideological when it came to supporting him. Bellatrix Black married one of the Lestrange twins and went to Azkaban for the decade and a half before Voldemort's return for torturing Frank and Alice Longbottom into insanity.

Those sound... Wrong-ish. Especially the part about Bellatrix - Fay is positive she prefers women, and also honestly pretty confident that she would not be married to either Lestrange for more than a month, tops, before widowing herself, even if she somehow ended up marrying him.