Sacrosanct
Legend
So, the druid won't be stealing the show when he shifts to bear form at level 2? I've been reading that this is, in fact, an issue,...
Where? Here? If you have, then I'm assuming you've also read MANY people with actual play experience say the hubbub over the moon druid is largely overblown. If anything, it's only really at level 2, and even then not very much. Just enforce the rules (only an animal they have seen), and unless you do a short rest after every encounter, it won't be all that noticeable from a OP standpoint.
So...
Does Barkskin work in wild shape form, or no?
How do you determine what animals a Druid has seen prior to the start of his adventuring career?
Barkskin does work, but remember that the druid will be level 3 before that even becomes an option. At level 3, every other class gains things that mitigates the perceived OPness of the bear shape significantly.
For your second question, whatever makes sense. If you have a basic understanding of ecology and habitats, you know that bears and lions and tigers don't live in the same regions.
But really, and this is the advice I keep giving in threads like these, is play the druid first and see how actual play goes before even worrying about changing the rules. 5e, more than any other edition in my opinion, is not good to do theorycrafting with because so many other factors that happen in game impact your guesses.