@Kaliph,
regarding with plotting drawing to greyscale, as said, AutoCAD Design Automation (DA) is a kind of headless AutoCAD on the cloud. you could firstly check how local AutoCAD works with the script, then move to DA. e.g. checking '-plot' command in AutoCAD help, you would find the script would export the drawing to greyscale pdf by a plotstyle:
-PLOT Y AutoCAD PDF (General Documentation).pc3 Y Grayscale.ctb \n
please note the spaces, which mean inputting default values. Grayscale.ctb is a default style of gray scale. I'd suggest you play it with local AutoCAD firstly to ensure the inputting.
If you need more flexible configuration on run-time of DA, you would need to produce your own plugin of AutoCAD by C#, VB.NET, C++, LISP. Most requirements have to be implemented by custom commands, instead of by built-in scripts only.