I doubt that taking the fork off a Dahon would shrink it much. Folded, the fork overlaps the rear triangle.
You would save a few inches by removing the wheels, but only if you also remove the rear fender.
BTW - I don't put my bikes in hard suitcases. I find I do better in duffel bags with thick foam surrounding the contents, and using my clothing to pad the bike. IME - airlines don't measure big duffels carefully, and it's easy to pass an overly large bag below the radar.
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