>>>I immediately thought that Pixelan Spices would fit there right on. Now I need to animate the spice. The easiest way is to keyframe luma. Unfortunately it does not 'wrap' lightest values to darkest.

You can accomplish the 'palette cycle' effect with Pixelan chromawarp. Apply Chromawarp to your spice bitmap.

set the first keyframe like this:
1 0 0%
1 0
1 0
1 1

then set the second keyframe to complete one cycle:
1 1 0%
1 1
1 1
1 1


you can type up to 32 into that field so you could complete 32 cycles using only two keyframes. in this case the 2nd keyframe's settings should be:

1 32 0%
1 32
1 32
1 1

this combined with the parent overlay settings yields some very cool results.