Your welcome.
Kontakt is'nt the same as Komplete Kontrol. It's Komplete Kontrol that use NKS as i have written.
You can't use Kontakt for the NKS files.
Have you installed Komplete Kontrol?
And yes, Arturias like many other music applications use midi CC. It's a generel midi standard and not NKS related.
The ressource path you have missed is probably the path you need to find Mellotrons NKS files.
Have you installed ASC? In the preferences of ASC you can see the ressource path. I assume you will see the path i mentioned.
Can't you find C/ ProgramData? (Not Program files and alike - but ProgramData)? Have you enabled Windows to show hidden folders and files? This is very important informations, to be able to see and read the NKS files in a folder.
I don't understand, why you can't select your Samsonite controller in the Mellotron.
Can you please post a screenshot of Mellotrons Audio and Midi settings, where you should be able to select it? I understand you can find, select and use your controller for NI software. Is that true?
In case have a DAW or a applcation for live performance like this
https://gigperformer.com/ that use the controller, then you also should be able to use Mellotron as plugin in those applications. And it would be a mystery for me, if you should not be able to find your controller in Arturias standalone applications.