Why are my messages hidden under the keyboard in the Hangouts app?
Apparently, this is also an animation issue. According to an answer for my dialer app, setting the animation to .5x fixes a lot of spacing/hiding issues on the phone.
To fix it, do the following:

Go to Settings &gt; Developer Options
Change Animator Duration Scale to 0.5x

Many props to Abid Rahman K for figuring it out!