I just did the above (except reboot). My suffixes do display, and I did have to type in my administrator name and password. I tested with a name that's in a .rtf and .epub in the same directory. It still found the .rtf.
So I went into the spotlight privacy settings and excluded this file and tested (no change), then went back in and unexcluded it. (no change)
I'll reboot later this morning.