I thought these could also be used:
Ramon Miranda - RM Sketch V1 bundle > RM Pencil 6B Tilted is found in the bundle
Fizzyflower’s MyPaint - Tanda > TANDA pencil-6b > direct link to the bundle because it is hard to find
Selk - 6B Pencil Krita.bundle is found in this topic > exactly here > 6B pencil Krita
For your coloring question, when you put the coloring layer below the lineart layer, it cannot paint over the lineart. So, just create a new paint layer for it and put it below your lineart via drag-and-drop or using the arrow buttons at the bottom of the Layers Docker. Like in this example:
Michelist