No I really don't think it is 100% true. For one thing, this idea of regressions and past lives and all these other sorts of processes were going on and Hubbard was but one flavor of this, since as I think I said before, with links and all, it was basically Freud who came up with the entire mental image picture thing, conscious v. subconscious (which he borrowed from the Romantics who really focused on it in the 1700s....), and the entire regression process (which Atack documented) was abandoned by Freud after he devised it. Ron just borrowed it and gave it a few snazzy terms. And there are others who do such things and who were never in Scn or even know who Hubbard is. The FZ shares lingo, that is true. I don't care for the lingo and try not to use it. My only wish for the FZ is that they examine what they do 'accept' in passing from Hubbard and remove the debris. (But even that is not a big deal since it would only matter if I was trying to get involved and I'm not really, so I never hear the lingo anyway except on esmb.) What I find is that what is left after doing so [removing the superfluous blather] was not even Hubbard after all. What he did was only poorly to interpret things already there.
For myself I have zero interest in processing or processes from any source. I don't need or want it I guess. The above comments and all I said before is just based on what I have observed so far, which is only to say that I think everyone should enjoy the FZ and have fun and do that if they want to, which is way better than CoS.
And from my own personal experience, nothing CO2 does is remotely Hubbard. It's unique to CO2 and Hubbard's tech is but the faintest trace. Sorry CO2 if I am wrong but that is how I 'experienced' it.
I don't see seeds of LRH there at all! [It's all CO2 and his own secret formula.]
I guess I have always viewed Freud as the source of all this, not Hubbard. And as you know, I'm not convinced by Freud that much either.