The mod crashes at startup in conflict with the latest Vanilla Fix, which has some Mixins updates in it. (MC 1.12.2)

Can't help without a log.

Apologies.... here is a sample log.
latest.log

Last person who reported this was using an out of date version of VanillaFix.

This is the latest VanillaFix-1.0.10-150.jar

The next build I am completely removing Mixin and the fact that its a CoreMod. Wait until 2.0.4. I'll put a build up of it shortly for you to try.

http://solder.almuramc.com/downloads/sgcraft/SGCraft-2.0.4.jar

Try this.

Well... it doesn't crash with VanillaFix any more, which is good. But I've not tested beyond that - is there a changelog to check or things to watch out for which may be impacted?

I will be available shortly.