Lots of folks get ranks not through Hombu or a super Shihan. I think its more a case of knowing how to play the scales in any key. Then you are ready to start learning to play music.
That's a long test list. Looks like fun. How many uke will you use during a test?
One uke for everything listed above, who is testing as well for the same rank.
When finished we will switch and I will play the role of uke - as you can see the test can take a lot out of you!
Also, typically it has been with someone from another dojo that I have never practiced with... which made things really interesting!
And for Jiyuwaza I will have two ukes for three separate types of attacks.
I tend to agree with your analogy by the way.