In your shader, you don't multiply the albedo by a color, which the standard shader does

I'll add this in the next version

I'm not sure if it's really something SF can or should have. It seems very case specific from what I can tell, and probably a bit out of scope. But maybe at some point in the future! Though I doubt it

It is somewhat buggy in the 4.x version, yes, and unfortunately I'm not updating the 4.x version anymore.
The lightmapping system shouldn't be completely broken though, if I remember correctly, it was in a few cases it didn't work.

That said, as the other person mentioned in their thread, they managed to temporarily fix it by adding:

half4 unity_LightmapST;
sampler2D unity_Lightmap;

To the code after each edit in Shader Forge. You should try that as well!

I think you are the same person as the one who posted on reddit, and I believe you fixed it by restarting Unity

And, glad you like SF!

Shuriken colors particles using vertex colors, so you simply need to add a vertex color node to your shader, and multiply it wherever you want it :)

The naming restrictions are still there. The problem now is that Unity's pipeline for lightmapping is heavily adapted for PBR specifically, and they've created lots of helper functions and structures that streamline their way of lightmapping things.

The problem arises when you want to do something, well, other than that. Their structures is still what keeps the entire pipeline running and if you want to break that pipeline out, you have to backtrack all of that code and filter everything for what you need. PBR is very, intertwined, in a way, because for instance, you have to have specularity, PBR doesn't make sense without it. But in Shader Forge, you can choose not to use it. But then you want to still access lightmaps built for a PBR pipe.

Another issue is that lightmapping has several types, which require branching, and custom branching is currently not supported in SF. The most complicated one is the directional lightmapping, which needs to run the entire BRDF twice, which SF doesn't support either.

That's, really odd. I barely know what that even is, it's not the Shader Forge code as far as I can tell. Looks like a constructor failed somehow. Might have something to do with your platform setting?

Not really, no, and lightmapping got much more complicated as of 5.0 :(