You're nearly exactly correct. On the last BIOS version (n-1, I forget the number), the VoodooPS2controller.kext was problematic and would only boot in safe boot mode. The reason removing it didn't seem to help was because my bonehead self didn't run myfix after taking it out of Extras/Extensions. Take all three out, run myfix and it was up and running with n-1 BIOS (although without the keyboard and touchpad) After updating the BIOS to A15, and putting all three Voodoo kexts back in place, it got a KP with one of the clearest errors I've ever seen. With that error, it was a simple matter of removing the VoodooPS2keyboard.kext (but leaving controller, which is key to the keyboard and trackpad working) and re-running myfix.
I'm unsure what, if any, problems will arise by not having that keyboard kext. But for now, it's a standard functional e6410 (everything works except SD card slot and sleep).