On several of my Simple Songs to Practice Scales, I do something similar, though I like to call it:
Single Notes
Dirty Notes
Lotsa Notes
I kind of did it on this song which I call:
TOGETHER
I progressively get a little “dirtier” on the bottom end, while keeping the high part of the song in single notes so as not to hit the dreaded -6 -7 evil sound:
On this one, the harmonica is all single notes, but on the piano I go from single notes, chords, then chords with the melody. I haven’t tried that yet on the harmonica, but I’m going to 
It’s funny to see these now, especially the last one. My timing is all over the place!
I don’t know what the heck my leg is doing, but it’s kinda going crazy. Definitely no steady beat. It seems to have a mind of its own. After using the metronome now for about a week, I can see what I’ve been missing, and how far off I am on timing, but I’ll save that for another post.
Keep harpin @yuriythebest