* * *Last night, I finally learned how to turn off "smart quotes" and other auto-corrected mother-henning on the iPad! In hindsight, it should have been obvious. Apple prides themselves on providing a seamless, well-integrated user experience. Apps have only the bare minimum of settings internal to themselves -- because most of the settings are global, or at least accessed through the "Settings" menu.
In this case, Settings > General > Keyboard > "Smart Punctuation" OFF. Done!
There are a lot of other elbow-jogglings that can be toggled on that menu as well. This change makes the iPads a lot more useful to me, since I greatly prefer Standard Manuscript Format and it calls for straight quotes.