I’m looking over the frame data, and this does technically seem possible. Close fierce has 4 active frames plus 15 recovery frames making 19. Frame advantage on hit is +2. That’s 21 frames. Light JK comes out in 20. So if you cancel on the first frame, it should be possible (or with even more leniency on counter hit). Of course, larger characters tend to be the grapplers, so I don’t know how practical a close-range combo into JK is, but EX JK comes out in the same number of frames, and that’d definitely be awesome to combo into.
If I weren’t so tired I’d try this right now.