Question Marks in iTerm (Font Issue?)
After a period of troubleshooting, and with some nudges from Allan, I was able to figure out what was going on: my terminal was attempting to display a unicode lock.
Turns out, my font, Inconsolata for Powerline, didn't support this. I came to this conclusion after reverting to my default theme in iTerm2 WITHOUT Inconsolata enabled. The lock displayed correctly there!
After research, I found a Github repo (and its name is familiar... I feel like I used it on a previous install) of patched fonts that display most of the proper terminal unicode icons. Much thanks to ryanoasis on Github for this!
If you're having a similar problem like me, give it a try and see how it goes. Here's what the fixed terminal looks like: