tsugaru jongara bushi, there is so many different tunes, am i correct in thinking that one uses the highlights form the original piece and creates new parts in between as one is inspired to?
basically so. A spirit is you do what others don’t do.
I’m thinking basically so as well. different improv versions and then those versions can be learned as so. On Shibata Siblings CD album there are 3 different versions of Jongara Bushi . 1 by Shibata Ai. 1 by Shibata Yuri and 1 by Shibata Masato.
http://www.hearjapan.com/store/group/Shibata_Siblings
Jongara Bushi is like a story that everyone knows and tells in their own way. The story always has the same beginning, middle, and end, but the characters are always different. As each Tsugaru Shamisen player develops, they inevitably create their own Jongara that is unique to them. It showscases their ability to control the bachi, their intonation, their dynamics, and their talent for improvisation.
Every player will have their own, as it is the trademark of our instrument, and speaks from the heart of the tradition.
If you go see a Tsugaru Shamisen peformance, you will no doubt be hearing that player’s version. A lot of the time it will be an extended version of what they played at the Annual Tsugaru Shamisen Tournament in Hirosaki (or any othe number of tournaments held thoughout the country).
Almost all of the techniques used in Jongara are recycled and pulled from other songs; merely rearranged.
Theres a lot of detail to go into with it, and ive spent years training for the tournaments and discovering new ways to play Jongara Bushi, so if you have a specific question, just shoot.
Hopefully that wasnt too much, lol.
i’ve been wondering about Jongara too 
and i liked your post Grant 
please do tell more!