My two cats have been tested for FeLV but neither of them have been vaccinated against it. They are both indoor kitties and neither of them try to escape so there isn't a credible risk of them contracting it. I spoke with several different vets about it and they pretty much agreed. Was Lily an indoor cat with her first family? If so, that could be a reason. The fact that she wasn't tested does worry me though. My prayers go out to you. I'm sure everything will be just fine!