Which one? I use 1KK against downed opponents. They usually block it, of course, but then get hit with 44B when they try to punish unless they know to use a long range attack. 88K is also a decent poke (and can also be expanded into an 88kA string). Else, maybe 77AA or FC A+B now and then. I rarely do her 2 A+B anymore.
I dont remember most of the moves you say... The rust... The effects... But anyway, irc 1KK is quite bad, slow irc, that's why they block it. I dont remember but it may be punishable as well. 88K I use it too, to mix it use just 88kA, the string is steppable, at least by Siegfried. The last three I really dont remember them, even though there's a version that could be quite good.
Try TRY to punish it, though! And eat 44B when they do. Though I had definitely noticed it doesn't always work against Alpha and Raphael seems to have enough speed and range to hit Leixia during 44B's startup.
But as Lei, you should be using stuff like FC 3B, 3B, 22_88 B, 'Im on fire', AA, 6KK, 4K, etc... Lately I was using CH 6BA, it seemed cool to me and if you can apply it on a W! it can be very damaging. 4A+B gives lots of damage too on a W! combo. But that's just my opinion on Lei, she isn't my main so someone who uses her more knows more