Um no, it's not the same trick at all.
(note: spoilers about fun 6 below)
The Fun 6 trick allows you to push the lemmings through the thin wall near the exit via a blocker. This works because the blocker prevents a lemming from turning around even when as it goes into the wall, until it has gone past the blocker's area of influence.
However, the case here in Mayhem 2 would, if you were to use the Fun 6 idea, require you to either A) push the lemmings vertically thru the 7-pixel floor where the exit sits, or B) maybe for you to push them through that steel wall so you can build above and across the flamethrower.
A) doesn't work because blockers have no influence on a lemming's vertical movement, so the Fun 6 trick simply doesn't apply in that manner.
B) might conceivably work, except you'll definitely need to use more than a blocker in order to get through the width of the steel wall, applying the Fun 6 trick consecutively until you get over. But the challenge requires 98% so you cannot use more than one blocker. Moreover, the game mechanics prevents overlapping blockers, so I don't think you can even apply the trick consecutively unless you have a way to remove the previous blocker placed, which is impossible with the bomber skills removed.
So, in summary, it's not the Fun 6 trick and as far as I can tell, it couldn't be.
