Firing up Xaramin and adding each of my *.cs files into the new project. I found there were actually very few issues building the actual C# code. The issues showed up when I was building the content using the MonoGame Pipeline tool.
So the initial results.
- Textures: Compiled no problem.
- Models: Required I exported them using the Binary exporter in Blender.
- Shaders: …..Some worked, some…not so much.
- Audio: Didn’t try yet since shaders essentially exploded.
Models took a little tinkering with, but the shaders were the biggest issue. Simple ones compiled, but my main model shader just spat out error after error after each fix i did, and often quiet cryptic, so this leads to where I am now, re-building the rendering engine feature by feature. Happy Days indeed :).