Place your image texture, normal map, and roughness map in one document in Photoshop
Turn off visibility of the normal and roughness map layers. Then use the Magic Wand Tool (W) and select the green background on the texture layer.
Invert the selection and apply a vector layer mask
I created a new layer and with the new layer selected, went to "...
The texture is problematic. On closer inspection it looks like scan of a B&W photographic print rather than a scan of the original. Old B&W photos often had a canvas like texture which was actually embossed onto the surface of the photographic paper, and it's a problem I've often encountered when scanning old photos for retouching.
Anyway, here's how ...
Unfortunately, with that background pattern from the old paper, I don't think you're going to be able to get it completely clean without some manual deleting.
However, if you use the Curves adjustment you can get it much cleaner before you do manual.
Open the Curves dialog:
Once in there, you can click on the far left or far right of the graph and move the ...
For Illustrator use Graphic Styles.
Create the appearance for one object, drag it to the Graphic Styles Panel. Then select other object and click the Graphic style you just created.
You can change/update a Graphic Style by altering the appearance and then holding the Option/Alt key down and dragging the object on top of the style in the Graphic Styles Panel....
Photoshop's line shape tool actually creates a very thin rectangle, which results in a double stroke effect when used the way the OP has described. The solution is to simply use the pen tool to create a line.
Use a text editor just change the font and color to the same value as the console your emulating.
A good editor can draw boxes and stuff, copy paste can make use of assets. If that's not enough use a ascii art tool. Obviously a text editor does not mean a word processor.
A Gradient Map might be suitable for your needs (although I don't fully understand your question).
It maps the values from a grayscale image to a color gradient of your choice.
Add the Gradient Map as an Adjustment Layer and the mapping is dynamically updated as you edit the image. No mask needed.