Looks like Steve is working on that, fortunately …
Not sure about that …
C# scripts are not even available for Rhino (but for GH only), which IMO is unfortunate when you have to (and can) use RhinoCommon, which is written in C#.
This also means that you cannot move C# scripts between Rhino and GH currently.
Anyway, let’s hope in CPython for Rhino 8, for both Rhino and GH …