Further research shows that you can LC a jumping enemy as easily as one dropping from a block.
When a pursuing enemy jumps after you, turn and wait for him (multiple enemies will screw it up).
When he's descending, run towards him straight along the line he's following. If you go at an angle, you'll have a hard time hitting him: I always missed unless I was in line.
Time it so that you jump into the LC animation just as he's about 1 to 1 1/2 body lengths above the ground, and close enough to hit (closer is better than farther; you can still get him if your feet press against him for a moment, but hyper-extension is your only reward for early launch).
Whango! He's dead. They don't fly as far as when you catch them flat-footed, I guess 'cuz of their forward momentum.
r_i, I don't know how to control the bug you mention. It surely doesn't happen all the time. (I think it's the same one that makes you go splodey when you jump near the edge of a block and land badly right on the edge; documented ages ago in leDoOd's
Hilarious Insta-Death Bug thread.)
I guess your comment that it "leads to an interesting possibility" is the point: you need to be alert and ready to take advantage of changing situations and opportunities.
BTW, the red and grey didn't come thru, but the diagram is clear.