No, not evidence for infecting her before, because Justine wasn't anywhere near that strategic position that makes her worth acquiring before BR (really before WN imo). Before BR, Justine was black sheep of the family Thomas's mortal girlfriend; that's basically it. There were much better targets for Nemesis to spend its finite resources on before BR.
Um, black sheep, a little crazy? Sounds a bit like Maeve doesn't it? Hmmm... Target, the brother of a star born who defeated He Who Walks Behind at sixteen... I'd say perfect positioning.
Like I said, your mileage may vary. Taking Thomas's character arc to "Psych, she never really loved you" is not a good storyline for me. I don't think that viewpoint would be uncommon.
That is your view point, mine is I think time travel is over done and way to easy a way out of things.
But that doesn't make those view points common or uncommon..
Before BR, Justine really is just some random mortal that Thomas fell in love with. Her choices and circumstances elevate her position only after BR, which makes that a good early bound for when Nemesis got its hooks into her.
No, she wasn't random, I'd have to go back and read, I seem to remember she was selected kine to feed the family, I seem to remember Lord Raith chose her for him.
For mortal Justine to be worth the resources for Nemesis to grab, she needs to be secretary to the White Queen at least.
Why? Yes, that is what she ended up as, but what she did, she didn't need to be secretary. All she had to do was become the lover of Thomas, and then get herself pregnant, she then had all the leverage she needed to get him to upset the apple cart.
1) Random mortal Raith picked would be compatible with Thomas for more than a fling
It may appear random, but not really, as a male, Raith saw his son as a threat.. The choice was a bit more complicated than merely random.
2) Justine would need to survive not being eaten by baby-rampire Susan; and that probably only happens because Harry intervenes in time.
However that didn't happen, I think you are confusing the end of Grave Peril with Changes.. Susan only becomes a full feeding baby vampire in Changes and we know what happened there, Justine wasn't at C.I. In Grave Peril Susan is half turned, but she didn't feed, now they may not have gotten to Justine yet, but Mavra was also there and chose some "take out" when she left, those poor kids were also unturned. So perhaps Justine got lucky or she wasn't messed with because she was already possessed by Nemesis..
) Justine survives fatal feeding from Thomas
Again, my point, how did she survive? Oh maybe she is possessed by Nemesis..
4) Lara takes Justine under her wing instead of setting her up somewhere quietly out of the way
Not so odd, Lara loves her brother and is grateful and knows how he feels about her. Either way it embeds Justine further and makes her even more legit, best cover yet.
If any one of those things doesn't go exactly right, Nemesis loses out on its investment of resources in the Justine plant. Nemesis would have had to predict all of those unpredictable outcomes years in advance. If it could do that, Nemesis should have ended reality centuries ago.
Nemesis has time, this isn't the only place that Nemesis is, it is a critical place, things don't always go exactly right, just look at how Harry's life has gone, it is full of "what ifs" and "but fors" Nemesis isn't always successful but that doesn't stop it.