I found a consistent way to search for Kenshi's toasty boost. It's another one of my crazy theorys, but if you remember my last crazy theory, it ended up being the pattern for most of the cast, so hear me out.
-It seems Kenshi has a harder time getting Toasty! to pop out vs certain characters, especially in mirrors
-As well, it seems the stage that Kenshi does it on either works, or doesn't.
With that said...
I have found a consistent way to make Toasty! pop out for Kenshi every 15-20 minutes. Here is how i've been doing it for the past hour
-Pick Courtyard Day
-Select Sheeva as your opponent
-Wait for the first Toasty! to appear, attempt your Toasty Boost...
-Leave the game on, try some combos with him for a good 15-20 minutes... try to take small breaks in between those 15-20 minutes and do a quick attempt on the first combo on the first round.
Either you will land it on that first combo, or you wont. It has worked consistently for me for the last hour. I have plenty of inputs to post for Kenshi. I will keep trying until this pattern is gone...
But maybe it will also work for you. I have also done it on the Belltower, but that was last week and not using my theory above.
Hope this leads you down the right path. I will post my findings in the next hour or so.
EDIT - Just landed it again, in 15 minutes. This definitely works. That is 4 times in a row now. I will test a few more times. Running out of inputs....