This used to be accomplished with a shareware panel called SmoothType. SmoothType version 2.0.2 works fine under 8.5, which is a good thing, because the built-in version is ugly . Font smoothing is a matter of personal taste, though, and you might prefer Apple's or none whatsoever. People sometimes tell me that my type looks fuzzy and is hard to read. PopChar 2.7.1, MyEyes 2.3.1, and Suitcase 3.0.1 don't crash the Mac on startup, but I've been having unexplained freezes in Eudora that went away when I turned them off.
Deadlines prohibit further testing.
Panels that don't work have been or will be upgraded for 8.5 compatibility. Costar label printers are not compatible with 8.5, but there may be a fix by now. QuarkXPress has a problem with text and buttons disappearing from its Print dialog box, but strangely the problem goes away when you have Kaleidoscope 2.1 installed. Nobody needs this upgrade. As yet, there is no software that requires 8.5 to run.