Finally just figured out that I'm an idiot lol. System Memory wasn't referring to available RAM, but to the phones memory (not the Internal Memory). I moved some apps to Internal Memory, uninstalled some bloatware, and decrypted it! Then I could change my unlock style to Slide. The reason I wanted to do all of this is because I wanted to try to make WidgetLocker work without having to slide on it then type in a PIN. Figured I'd post my solution in case anyone else had a similar problem.