She became worth it the moment she became kine for the immediate Raith family.. Big clue here, she's insane, but feeding on her makes her sane?
I'm sure there are dozens of them at any given time. Papa Raith liked to surround himself with them as bodyguards before BR. Why not porn star Bobby that Inari fell in love with too? He'd be the boyfriend of Harry's brother's sister. Maybe Nemesis's plan to install him as the Merlin's personal butler just hasn't come to fruition yet.
But Maeve was infected, not possessed apparently.. As far as that goes, Maeve never had a "handle" as you call it on Harry, but Thomas did as of Grave Peril.
Maeve is important completely independently of Harry. The Winter Lady is a great target to wreak havoc on the balance of reality. A mortal Raith girlfriend is not if that's the best credentials she's got.
Nemesis has the time... All that time it has someone on the inside, watching.. Hence the name HE WHO WALKS BESIDE, that is someone that goes along, they don't interfere they are just there watching and taking in information.
But at the time you are proposing Justine was taken, she wasn't on the inside watching. That's the whole point. She's not worth taking before she was in a good position to do that.
Or because Justine was already possessed, Susan couldn't have fed on her if she wanted to.
Go read the end of GP. Justine was fed on by the other rampires. She shows Harry the bite marks.
That isn't Lara's style.
It would have been kind, and Lara is sometimes quietly human when nobody is looking.
Yes, but that was before Margaret's curse, Papa Raith isn't the man he used to be. He wasn't going to use Nemesis to take out Thomas, but use Thomas by way of Justine..
Papa Raith never fed on his sons, only his daughters. Nothing changed there post-death curse.