harlan
This may be more info than you asked for---but you did ask
The problem is that Miyagi had a number of students and the guy that probably would have taken over for him as the effective "head" of Goju was killed in WW2.
Miyagi seems to have taught in the "old style" where he taught the same kata to different people in slightly differnt fashion--kinda tailored to each person individual needs--their specific strengths and weaknesses.
Which is pretty much how all karate training used to be done--and one reason why you see so much variation in karate as a whole.
After they mastered the system each student then kinda went their own way--set up their own organizations etc.
(I don't think any did so while Miyagi was alive)
So each group of Okinwan goju is doing thing a bit differently.
And the Japanese goju guys are doing things "their" way as well.
The difference range from very minor to significant.
All can be broadly classified as Japanese or Okinawan, and all are doing things close enough to the "same" to see whom trained with whom.
Best I can do is say that the differences your looking at are probably "standard" withen the specifc goju organization that the performes belong too.
And they probably all fit the "umbrella" standard of "goju."
But there is really no "uber" standard for goju.