Not yet, but I'm working on it, so there will be soon.

They should work fine, but I haven't tested it too much. The only thing is that you won't have the expanded section on the node for the transform. 

Yes, these nodes are compatible with Cycles and EEVEE, except for the 3D SDF Preview node, which is only compatible with EEVEE.

Technically, these nodes will work with all coordinate spaces. However, some will be more useful than others. Object space and UV space, in particular, seem to be the most useful, but you can also do some fun stuff with screen space coordinates. 

Sort of. These nodes will only work in Blender. However, you can bake what you make into a texture and use that to bring it into the game engine of your choice.

Yes! SDF NodeBox should be compatible with all other shader nodes/addons/asset packs as long as they can work with greyscale gradients. SDFs don't do anything crazy under the hood. All they are is some math, so there shouldn't be any compatibility issues. 

Yes, I'm currently uploading a tutorial series on YouTube explaining SDFs and walking through the examples included in the pack.

I highly recommend checking out Inigo Quiles's website. As far as I'm aware, he is the expert on SDFs and has a ton of articles on his website about them. He even provides all of the code and math for them under the MIT license. A lot of the math for these nodes were originally from him. But seriously, go check him out, he has a lot of really cool stuff to show.

I recommend messaging me through Blender Market.

The category information is included inside the "blender_assets.cats.txt" file, and there are two ways to install the asset pack to make sure that these categories go along with it.

The first is to install the asset pack the same way you would install an asset bundle. Open up the included blend file, but make sure that it's in the same location as the blender_assets.cats.txt file. Then open up the asset browser and make sure that it's set to "Current File." from there, you should have the option to "Copy Bundle To Asset Library." This will bring in the provided categories along with the nodes.

The Other way is to just create a new asset library path pointing to the blend file. To do this, first, create a new folder in a location of your choice that is outside any existing asset library paths, and make sure the blend file and blender_assets.cats.txt file are both in that directory. Then open up Blender, go to Preferences -> File Paths -> Asset Libraries, and click the plus icon to the right to add a new library path. Then, simply point that path to the new directory you created.

For sure, Included inside the provided blend file are 5 example scenes using nodes from this pack to create various effects, including masks, textures, models, etc.

These example scenes can be accessed from the scene menu in the top right of the Blende UI:

SDF Nodebox currently contains 46 Asset-browser-compatible shader nodes and 5 example scenes to show how they can be used.

The contents of the pack breaks down as follows:

• 13 2D Primitive SDFs.
• 15 3D Primitive SDFs.
• 16 Operations.
• 2 Nodes for previewing SDFs ( 1 2D Preview & 1 3D Preview ).

Yes, the materials you create with the nodes can be baked down to a texture the same way you would bake any other procedural material into a texture. 

I'll also be planning on creating a video tutorial for this process sometime in the future.