Eureka! Did some homework on ocarinas and even did a few test to verify how my MPMS v2.1 3D printer and Cura were handling certain print settings and structures. I came to the conclusion that I must be getting under-extrusion or some sort of surface shifts or something inside the ocarina. I saw them on the outside and worked out some ways to get rid of them. While working through some stratagies to get better prints, I decided to test the premise by printing an ocarina with 10 walls and solid infill. I want with so many walls because it followed the ocarina's body path and didn't just print lines back and forth like the infill. The result was the clear with blue ocarina. The high note was heard for the first time. It was weak and flat, but present. However, the high F really wasn't what I'd consider usable.But it was there! The ocarina was a lot heavier than my other ones too.
I then dropped down to 5 walls and went back to 10% infill - blue with red. The high note was still there, but still very weak and not really playable. However it confirmed that I was on the right track and didn't need 100% infill.
So did some testing and was able to get rid of my vibration ghosting in my X axis and noticed that in Cura, when I thought I was reducing my print speed it was in fact doing NOTHING. When I was adjusing a PLA profile months ago I had set the Wall speed settings to arbitrary values, NOT, calculated. While my outer was was at a reasonable 40mm/s, the inner wall was set at 80mm/s and likely causing significant under-extrusion. I say that because when I did a test print with 80mm/s on the outer wall it was under-extruded. The machine just can't do it cleanly, though I was really surprised that it could make otherwise decent prints at hat speed. Anyway, I set Cura to automatically adjust my speeds with 40mm/s on my inner walls and 20mm/s on the outer walls. I also increased my extrusion to 105%. My total print time came out to just under 2 hours and it plays each and every note as expected - red with blue ocarina. The high E and F are loud, though not perfectly in tune. However a bit of sanding and better breath control should fix that.
I've learned a lot with this project and send my kudos to Karuuv. Great design! I stuck with v17, but also did my own modified version using the blender files that were posted. I'm testing it now. If it is any improvement, I'll share my results. I did do a v17/v13 blend, but didn't see any noticeable difference.
Monoprice Maker Select v2.1