I bought KQ2 for the Atari ST back in 1987 – indeed, in that version, if you type “What is Graham’s last name?”, the response is “Cracker.” I also have a faint memory of the “synonyms” thing you described… I think I actually tried it once, and thought “Hmm….”
OK, let’s try it on my version from “The King’s Quest Collection” (a 3-CD set from the mid-to-late ’90s)… The “Graham Cracker” question doesn’t work, but the synonyms do. If you don’t have a game saved in the quartz tower, then press ALT-D, type “TP,” then enter 90. Then you can type “look [synonym]” (racy slang for “woman”). I tried a few off the top of my head, and they all worked… some programmer was having too much fun.