You can totally have an adult in Nikita's pack if that's what you want. Honestly, that might even work better than a youth because she'll want people with her for this mission that have a little more control though a youth wouldn't be beyond belief if this is treated like a training opportunity.

Unfortunately, the internet doesn't yet exist because this game is set in the 1800's. Think more Van Helsing and less Underworld. There is the possibility for spreading information via pamphlets, but it would be a lot easier to track down who was spreading the information, thus endangering your character a lot more than an anonymous blogger. You'll also want to consider how your human relates to the main three subplots. For instance, is the human how they're going to find the compound where the lycans are imprisoned?