Finally got a perfect Ibuki run, this is probably less than a second off of TAS unless there's a speed strat I missed. I was really annoyed that my last Ibuki WR (the first ever sub-4 minute Trials run) had an accidental pause that lost time for no reason, so I had to grind out a perfect run.
On Trial 6 I figured out that Close HK sjc HK Command Dash is 0.3 seconds faster than doing DP xx FADC U2, and it's much easier too. However it's a little finicky, there's a 3f window where the U2 juggle works but the middle frame doesn't work, so you want to do it as early as possible to guarantee one of the correct frames.
The Trial 24 strat is pretty hard, but I found an execution trick that really helps get U2 without doing a QCF in the wrong direction. You can just slide from down+back to down+forward on the first QCF, then end with a QCF facing left. You don't actually need to input a full quarter circle so doing it this way means that you can start your U2 motion before you've fully crossed under Dan.
If the Trial 24 FADC strat is too hard and you want to try for a good run, you can instead do Dash x3, then end with MK xx SJC EX Tsumuji, juggle U2 which only loses about 1 second. If you don't get the super jump before EX Tsumuji, you can also do the U2 input ending in Up+Forward, so you have 2 chances to get it right.