Yeah I'm sorry, but I don't think I can say that much more on this custom system of yours... The compiler-generated code is impossible for me to figure out, and I can only really give support on my own code... I fully support writing your own extensions, but apart from how to write the implementation, I can't help further than that!
So... if you can load custom emoji as quads, you can load any image as a quad! If you go through the emoji code, what you can do is take the part that looks for an emoji based on file name, and adapt it to load whatever image in a Resources folder as a quad. When you grab the image as a Texture2D, you can even use the dimensions to determine the size of the quad.
And I'd still recommend just using a standard image/spriterenderer for this if your banner is on a different row, anyway! That way, you can just skip applying it to a quad, and put it right on an image renderer.
