It all depends on where you place the mixup at. I've done it at higher levels of play, just about conditioning your opponent. And yes, flea stance is actually really solid. I've been using it more and more.
challenge accepted
The thing I don't like about this is you're telling your opponent "hey I'm going to mix you up now" and once you've done that, they're now equally capable of choosing ducking or standing, and iFC3K/4K is really bad risk/reward if they're ready for it.
You can kinda mentally pressure them the threat of DGF options, and that can make it hard for them to adjust their thinking when you cancel and do a different mixup, but that requires you to actually use DGF options, which can get you hurt or just be a waste. That just makes me question whether its worth doing the cancel at all, because there seems to be no reason not to just do iFC3K or 4K (or a better mid) without any warning.
For a new SC5 Yoshimitsu player, should I just grind endlessly in Practice mode trying to get iMCF and a:B+K down, or should I just try to ease myself into the character with his other moves? I just feel like I absolutely have to get those two moves down, in order to effectively play the character.
Also as far as stances go, any particular stances I should try to avoid using a lot?
Finally, one last question as a SC2 Yoshimitsu player: Does Suicide win you the round, even if you end up dying from it? I know it does this in SC2, which made it actually viable in that game.
In other news, I really miss his SC2 1AAA, in this game...
If you really want to learn those moves, practice every day for like a week for 20 minutes just doing those two moves, and practicing doing things into and out of them. You can't buffer them, so to get the most out of them, you need to know the exact timing of recoveries. Then just learn it by playing the game and practicing between rounds.
The stances are just ok. Good players will have strong responses to them, and you need to be creative in order shake things up.
2B+K stance is often beaten with a backstep or counter-attack at the timing of the teleport, and to shake things up you can heal to bait them and carefully time a 6A+BK (penguin slide) or do an IND move.
For 8B+K stance, good players can duck and react to the mid, and you can mess with them by stance cancelling and taking advantage of the passivity of their option coverage.
For SDGF, they can just step and react to everything, but delaying or doing A+B movement can mess with their step timing, and weird options like SDGF B+K or G can put them in unfamiliar territory.
B+K stance is decent since it's safe and causes a lot of guard damage, but it also doesn't have much of a mixup, since the lows are punishable even on hit. Just hopping toward them once and hopping straight up a few times is actually kind of hard to stop and does good damage on hit, with the combo being: hop on them again, 6(6). Hop into the stance B is also a frame trap. Stance-cancelling after landing and mixing up is pretty good too. Though hops could be stepped, or GI'd if they have good reactions, but that hasn't happened to me yet. Transition to it with 2(A+B). Another use is just doing B+K in response to a mid/throw mixup, if they throw do the FLE K ~DGF A+B combo, which does damage in the low 80s. Even if they do a mid, you're in the air so you (usually) can't get launched.
Suicide is still really good. Other than causing a double KO when you're about to lose a round, you can also win any round if you have a big enough lead. When you're 2-1 or better you can also win the match with a double-KO. This isn't SCII so people won't be stepping all the time. Get them to think about mixups and this move is guaranteed to hit.