Makoto's ability to 100% stun characters

Alex ------- Yes (90% stun) (no kara)
Akuma ---Yes
Chun-Li - Yes (https://www.youtube.com/watch?v=10afDcJ5VXA)
Dudley --- Yes (90% stun)
Elena ---- Yes (no kara)
Hugo ----- Yes (90% stun) (no kara)
Ibuki ------ Double Kara (2nd kara is Cr.HK)
Ken ------- Yes
Makoto --- Yes
Necro ---- Yes
Oro -------- Double Kara
Q ---------- Yes (90% stun) (no kara)
Remy ---- Yes
Ryu ------- Yes
Sean ----- Yes
Twelve --- Yes
Urien ----- Yes
Yang ----- Yes
Yun ------- Yes

Double Kara = You have to kara the last LP Fukiage as well with Cr. HK
No Kara = It means you actually need to not do any kara to hit.