So while messing around on console, I discovered a way to get the blue jinjo underwater without pressing B and without it waving, but I am having a hard time getting it consistent and figuring out exactly how it works.
First, I have done up to entering TTC and I have collected the first 4 notes in this order: bottom left, top left, top right, bottom right. From here, if you jump to the right off the dock and hold left, you can get "caught" on the fence/edge and sometimes you will sink deeper in the water than you normally would, collecting the jinjo in the process. In slowdown I have no problem getting Banjo stuck but I haven't been able to get him to sink deep enough. On console usually I can get it within 10-20 tries but it's hard to tell exactly what specific collision causes the deep sinking. If anyone could help me look into it, that would be much appreciated.
I'll post my stuff here
https://www.dropbox.com/sh/zh7kztmv5dpbxyv/AAAowNh1eSuZ2eV-59RMheYaa?dl=0 so anyone can try it.
EDIT: Unfortunately after testing done by some Banjo runners on bizhawk, we concluded that this trick does not work on emulator due to some sort of physics phenomenon that only seems to exist on console. A BK runner, Benjacastellon, found a different way to produce what I found by fluttering against the fence, and it is relatively consistent now on console. We tried the same thing on emulator for hours to no avail.
Additionally, it is not worth it to wait for the jinjo to wave. The jinjo cannot wave unless it is standing still, and because it follows Banjo in a circle as you collect the notes on the dock, it will not wave in time for this strategy to be faster.
Back to the original way to collect the jinjo!
