OK, so here’s the deal. After doing chicken combo (or 2-hit MP vs. twins and Hugo) into whatever yagyou is necessary, and getting on the other side, the most damaging way to break their guard is neutral jump HK. Afterward, you do close MP again to continue the cycle. This isn’t any revelation, I’m sure.
HOWEVER, some characters can avoid neutral jump HK altogether by crouching, as this allows them to block/parry the string. These would be Dudley, Chun, and Makoto. There’s also the Shotos, who require different timings for neutral jump HK if they’re standing or crouching.
Now, sure, there could be ways to make this a guessing game of sorts. But getting an opportunity for unblockable loops is rare in the first place, so I want something that works with the same timing, every time. Here’s what I’ve found…
vs. Shotos: Do far s.MK after jumping over them. IIRC this gives the second-best damage and stun of any of Oro’s medium attacks (the best being his close MK), and it will actually allow you to combo close MP afterward. I forget if you can use the close MK for this or not…
vs. Dudley: Chicken combo into MP yagyou, then dash once to push him forward (he has to be pretty high up in the air for all of this). Jump over him while he’s in the air, and without moving do close MK upon landing.
vs. Chun: Close MK seems to be iffy. Far MK whiffs if she crouches. c.MK works consistently, though I hate to use it because it does no stun. Actually, I’m not even sure any of these really hit meaty against her (you have to walk forward just a bit after jumping over her).
vs. Makoto: Close MK seems to work, although I have the same issue as with c.MK vs. Chun.
So, just something to let you all know about. =)
EDIT: Removed Tweleve and Urien from this list after I learned how to perform j.HK unblockables on them (thanks to Streak).