K, you can't get a Chespin with Bulletproof like that, to answer your first question.
You can get Quilladin in the Grass Friend Safari and you can breed it to get a Chespin with Bulletproof.
Other ways to get Hidden Abilities are to get Friend Safaris, Hordes, and events (only one so far was the Torchic). When Pokebank comes out, you can transfer those Pokemon with Hidden Abilities and breed them.
Things to look at: