Finally got it! All that needed to be changed was position:absolute to position:sticky, which put the links back at the bottom of the page, and then I adjusted the specific numbers (especially height) until the main scroll bar vanished, leaving only my custom scroll bar. Your help was invaluable, as was my annoyingly clever brother who doesn't even know anything about #ccc stuff or html, lmao. The asshat just realized that overflow and position had to be functions due to the words after the :'s looking like parameters, and then he googled it and found absolute, static, sticky, fixed, and relative, and we tested all of them until it worked.
With it on position absolute, for whatever reason, everything typed at the bottom of the div tag looped back to the top, including the links (note: if anyone ever wants their links at the top of the page, well, this will do it!). Now the links are back at the bottom, AND the normal scroll bar is gone due to my custom scroll bar and use of blank paragraph lines making the window exactly the normal default popup size.
Of course, this may not work on other browsers, and almost certainly won't work on mobile. Not to mention, changing the window size will likely undue all my hard work. But I am quite pleased. If I adjust the numbers right, I can actually completely remove all vertical scroll bars from the default size window, but I figure that would be confusing, so I'll just leave my smaller one visible.
Anyway, if you ever need free 8 ratings, Ogre11, don't hesitate to ask!