Question: Why is it that the aliens, who obviously possess technology and intellect far beyond humans, didn't think to use their pictographs to communicate right out the gate? We had to wait for Amy Adams and her dry erase board?
Answer: The Heptapods' "present" encompassed about 6000 years of our human past, present and future. So, they perceived 3000 years of our past and 3000 years of our future simultaneously. It's a confounding idea to humans, but the Heptapods already knew, 3000 years in advance, that Louise was the critical contact for the evolution of communication between our species. For the Heptapods, there was no coincidence or impatience or blind luck; they already knew exactly when and how to start communicating with her.
Answer: The aliens don't see time in a linear fashion but all of time at once, meaning they can see the future, which is why their writing is like it is. They therefore knew Louise (played by Adams) would be the one to figure out their language and had to wait for her, or simply chose to wait for her.
Answer: As a result of the tortures he endured at the hospital, Lockhart lost his mind. At the end, as he pedals away from the hospital and down the road, he grins maniacally because he is now quite mad.
Charles Austin Miller