Hi, liz,
Your legal question probably is more in line with Darth J's expertise than mine. But I'll explain how I would see it.
The area of the law that would be implicated would be torts. To succeed in a suit, the abuse victim's attorney would need to identify and prove to the jury:
1-a duty by LDSC and/or bishop
2-a breach of the duty
3-the little girl suffered damages (that would be the easy point to prove), and
4-those damages are the 'proximate result' of the breach of the duty.
##1 and 2, duty and breach. Those are the hard parts of this case. We all have a legal duty to act in ways that do not create an undue risk of harm to others. The greater the risk, the greater our duty to be careful that others are not harmed from our actions. My walking through a restaurant does not pose that much of a risk of harm to others, as does driving a 3,000 lbs. car at 75 miles an hour on a freeway. I have a greater duty of care to avoid harm to others when driving that care than when walking through the restaurant--but I yet have some level of care that I must exercise even while walking through the restaurant.
LDSC created the context and environment of the Sunday School class, an adult teacher, and parents wanting to see that their child attends the class. LDSC created the context and environment of the bishop selecting who the adult teacher would be, what would/would not be asked in the bishop's interview, the dynamics of the ward sustaining (and possibly objecting) to the calling of the adult as a teacher, and under what circumstances and compunctions another ward member would be inclined to notify the bishop if the ward member spotted something suspicious. So, that action of creating those contexts and environments involves a duty of care on the part of LDSC. The legal question for any institution creating such contexts and environments, did LDSC take reasonable steps to protect others (including this little girl) from harm given the level of risk?
As our society has become increasingly aware of adult sexual abuse of children, and specifically the LDSC situations, LDSC's legal duty of care has increased as well. Given the Boy Scout cases involving LDSC, it is legally required to take extra care now knowing that such problems and abuse has taken place in the adult-children activity situations. Has LDSC taken reasonable steps of heightening the care it is taking to avoid this egregious, and heightening, risk of harm? For example, while other institutions in our society are taken the steps that Jersey Girl outlined to prevent an adult from being alone with a child, has LDSC lagged behind in this regard?
These are questions that the jury would have to consider and decide.
For the bishop, he shares that duty with LDSC as its functionary in this situation. As LDSC's representative, what he might have specifically known about the perp's background--both when extending the calling and later as he continued in it--is crucial. "What did he know and when did he know it?" The law is all about holding people responsible if they did not act appropriately in light of the information they had or was reasonably available to them. But another question is important. What steps if any did the bishop take upon learning of problem behavior by Ryan Whittaker? If there was no reason for the bishop to be suspicious until after the entire matter broke public, and then he reported it to the civil authorities, the bishop is probably not legally liable. The only possible question of him is why did you put a man in that classroom with those young children rather than a woman, given that sexual predatory practices are more likely among men?
Even if the bishop is exonerated, LDSC yet created the contexts and environments that could be problematic. Suppose that two members of the ward had reason to suspect pedophilia tendencies by Whittaker, but kept silent during the sustaining of the calling process and later never mentioned anything to the bishop? See Drifting's observations
here. They might explain that dissent is not encouraged in LDSC, and so is assuming that the bishop already knows what a member likely knows. There is, in the LDSC scheme of things, the concept of repentance, after all.
What if the bishop was aware of some untoward conduct by Whittaker, inappropriate towards children, maybe hints of sexual overtones, but nothing that rose to the level of required to be reported to civil authorities. The bishop learned of this through Whittaker's confession, or contacted him for a repentance process after learning of it independently of confession, but the bishop thought Whittaker has successfully repented and was 'cleansed' of these bad thoughts and flirting actions, and so put Whittaker back in the proverbial candy store? I think he'd have problems.
##3 and 4 (if ##1 and 2 are established to the jury's satisfaction) would be easy. No doubt the little girl was damaged, and a significant cause-and-effect relates it to the duty and breach by LDSC and the bishop (if ##1 and 2 are so found). Actual monetary damages would include the cost of medical and counseling services. The jury would also be able to assess pain and suffering damages.
Of course, if the perp, attorney Ryan Whittaker, has substantial assets, he'd be a much easier target to establish legal liability against.