I assume you mean 1.12.2.
You need to create a custom recipe factory. Specifically an IRecipeFactory and an IRecipe implementation for your factory to return. You can read about them here.
ItemStack#getTag() and ItemStack#setTag(). Get the tag and if it is null create a new tag. Then populate the tag with your own value(s). Then set the tag if it was null.
That's exactly what should be happening
The blockstate should have no say here as long as it has the ANIMATION PROPERTY which is does.
The static variable lets you render one model without animation at all and another model with animation. I believe they are rendered at the same time.
Spamming isn't going to get you help any faster. After downloading forge run the installer to install it onto your client. Then take the mods you want to use and put them in .minecraft/mods/ if it doesn't exist create it.