Currently when both mods are installed, the game window just doesn't show until the SplashAnimation bit ends (or maybe it just skips it?), and then business as usual, so I figured compatibility might not be too difficult to implement?
Would be great to be able to ship both mods in a modpack!

I think splash animation will replace the whole launching process?

@kappa-maintainer Splash animation is usually a few seconds long, followed by a fade out into the loading screen - which is the vast majority of the launching process (you can see an example of this with The 1.12.2 Pack or Hexxit II).

This could be fixed by making splash animation run after Mixin and targeting the correct class in my mod. But I am busying with irl things, you may need to ask others to recompile splash animation.