*Mod Version: 1.12.2-3.4.9.11

*Forge Version: 14.23.2.2654

*Link to crash log (if applicable): https://gist.github.com/Nargath/0c0fb535ec63ec20a6104d389755a159

*Description: Minecraft loads almost all the way through the pre-launch stuff, but crashes out just before it gets to the first menu.

Update your AmibentSounds to the latest version.

That did it!
Thank you for the advice, and sorry for the run around. I honestly didn't see that Ambient was still in my modlist!

No worries. The sound engine crash patch was integrated into Forge directly and both CreativeMD and I had to make changes so we don't try and apply the patch again and cause a bunch of problems. You aren't the first to report this, and I doubt you will be the last. :)