Gen Fu:
YES...

...the differences between whether he parries a punch or kick are significant. Like Lei Fang, he switches positions on a punch, and not with a kick. This MAY screw up the needed buffering you need to do to take advantage of the parry. IMO, this is what makes using Lei Fang's a bit harder in comparison. She lacks a useful move that is "input neutral" in terms of "direction" to make things easy for her. However, with smart move selection, Gen Fu avoids this. Note too, that because Kasumi's parry outcomes are consistent (she always switches positions), this is not an issue.

Gen Fu has a 16 frame advantage. Sadly, his [d/b, f+P] is also 16 frames, and therefore is not guaranteed.
HOWEVER, a [d+P+K, P] IS guaranteed (barely though, it's 15 frames means you have to have exact timing... but it's easy to buffer). And this is the move I was hinting at, at being "input neutral". Perform the parry, be ready to perform this move, and it doesn't matter if you switched positions or not. It should be noted that the [d+P+K, P] is very damaging, and detects walls at the maximum 5 metres.

Note too, that when it comes to parries, although they require an extra input, so do advanced holds. But they work on 2 levels instead of 3 (or even 4, if you use advanced mid-holds). Because of this, they are potentially easier to use than advanced holds. While the extra input means they cannot be performed on reaction at the same level that normal holds can, normal holds still work on 3 levels - that may balance out, or that may not, depending on the user.

Another very important thing to consider is that you cannot "break" a stun with a parry, like you can for a hold.