If the question is "Should Wednesday, while not exactly choosing to believe religion, avoid thinking about it too hard because she thinks doing so will make her an atheist?," then she's already an atheist on some level because she thinks knowing more will make her more atheist, which implies atheism is true. This reduces to the case of deception, which you seem to be against unconditionally.

That's not necessarily true. Perhaps she believes Mormonism is almost certainly right, but acknowledges that she's not fully rational and might be misled if she read too many arguments against it. Most Christians believe in the idea that God (or Satan) tempts people to sin, and that avoiding temptation is a useful tactic to avoid sin. Kind of like avoiding stores where candy is on display if you're trying to lose weight, say. You know what's right in advance, but you're afraid of losing resolve.

Certainly whatever your beliefs, some people who disagree with you are sufficiently charismatic and good at rhetoric that they might persuade you if you give them the chance. (Well, for most of us, anyway.) How many atheist Less Wrongers would be able to withstand lengthy debate with very talented missionaries? Some, certainly. Most, probably. All? I doubt it.

Overall, though, an excellent response, and I agree with almost all the rest of it.