Alfred had discovered what happened to these two young masters after Luke downloaded SHIELD's classified files.
Alfred wouldn't have picked them out if they hadn't been connected to Luke; they were just small fry in a pile of 'research material,' and were just footnotes in the classified files.
So, Phil really had plenty of ways to control Ryoko Tamiya.
On the other hand, exactly how effective the means were and how long they could last were up in the air.
Thinking for a moment, Luke decided to give his uncle some face. "You can have her, but we want half of any results you obtain. In the future, we get a copy of whatever information she provides on Parasites."
Phil agreed readily. "No problem."
I'm not done yet, why are you in such a hurry? Luke couldn't help but roll his eyes. "Since this is an investment, I'll do my best to reduce her risk level before giving her to you."
Phil: "…Thank you."