I'll share a few things. 
I'll try to be 100% accurate, but if there are any errors I will be happy to be corrected.

Afaik, Joel, Barry and I all have Jewish upbringing.  I was raised in conservative social judaism with Hebrew school for some years after regular school.  Joel and Barry afaik tended more to the radical leftist movements. (I have a little fun with them by talking about their Hegelian dialectic way of looking at things. In other words, I believe a residue of their old leftie, secular thinking can still rise up, interfering with the heart of God in the Christian perspective. Thus they got enamored with faux scholarship proclaiming yahweh/ And 15-20 years later sought out a dialectic that would allow yahshua.). John Haldenstein and dear brother Noel Rappy (1953-2014) were other early Jewish members, and Shoshana Cohen. John was involved in apologetics, when they really wanted to understand Bible harmony. Noel Rappy was the drummer, for a short season.

Interestingly, Barry tried studying with the Lubavitcher Chassidim in Brooklyn right in the period before he came to faith in the Lord Jesus (and even with a smidgen of overlap, he brought some Lubavitcher-based questions up to Blair Adams.)  Barry's testimony on some of this stuff is fascinating.   And I probably had more Hebrew background than those two, and my background was very light. I did have a full Hebrew-speaking Bar Mitzvah although it was essentially phonetic. This has helped me a little in sniffing out the truths when it came to the cacophony of claims about the Tetragram. Remember, I even got mired in the sacred name movement (mostly yahweh and yahshua, with pressure to avoid Jesus) myself for some years after I left the fellership.  However, my hunger for truth and consistency and the Holy Spirit led me out of that mess ... 100%.  While Homestead Heritage was getting sucked into mirey clay.

Joel and Barry .. neither had a real Christian perspective and heritage, only the limited orientation that they received in the fellership. Understand, in the 1970s there was nobody with a real deep Christian background (Blair's was reasonable but it was not historically deep, he was not really up on Reformation and Baptist and pure Bible movements, more simply the oneness heritage. Although he has maintained some of the traditional apostolic respect for the AV, even while the fellership as a whole went downhill quicker after 1990.) The members drew largely from former hippies, catholics seeking more and a mixed milieu that included a some inner-city folks too that responded to the depth of the evangelism. Those were days of purity, Christian doctrines were generally sound, even if the ministry did not have great depth of background.  The big weakness was how they let yahweh slip in, but it was minor for 10-15 years.

There was also nobody with a real Hebrew background.  Joel has been in way over his head in all the studies of theophoric names.  And in the fellership once something heads in the wrong direction, it is very hard to make correction, especially if it would mean acknowledging a major error by the ministry! This possibility, of a fundamental mea culpa, grates against their ministry perfection, we are Jesus come in the flesh, doctrines.

It is truly amazing to me that even in the later period of the 1990s they added more blunders and errors by incorporating the counterfeit yahshua. This they hid from me in our years of interaction, and I only learned in 2016 though the former members. (Not a word of yahweh or yahshua squeaks out to the website.) Remember this bogus yahshua thing has even polluted the formerly apostolic water baptism.

Amazingly, they even had Israelis involved at that time.  Yet everybody knows yahshua is bogus.  They could read and speak to Nehemia Gordon, or Michael Brown or Randall Buth .. in English or Hebrew... or any scholar or solid Hebraist ... and learn quickly what an abomination is yahshua.   They were pushed into sophistry and into advancing the bogus yahshua by their desire to match up with yahweh in the unfolding name and the yahweh-worship doctrines.  They hid these blunders in literature that was kept internal. Insularity bred error. And error begets blunder begets spiritual travesty. And the Israelis and seminarians are to blame as well, since they could have insisted on correction. They likely had to cover their eyes and mute their tongue when they were told to start accepting "yahshua". I think one of the Homestead Heritage tricks was to wait till the people are really enmeshed, and then spring the ultra-problematic errors. The idea is that by that time there will be an overriding acceptance of ministry authority, and faux doctrines will be ignored.

In 2006, Joel piddled around, theoretically researching Jehovah and yahweh. Our correspondence began then, and stretched for years, although it was not continual. (At the same time the literature was advancing to be more and more yahwehistic, a point never mentioned by Joel.) However, Joel has always been praying or giving words of prophecy to "yahweh", so asking him to discern the truth about the name, when he is praying to yahweh, it is a bit like asking the wolf to check security in the hen house. Barry, his research assistant, a wonderful brother as well, long has had YDS ... yahweh delusion syndrome. 40-45 years of this error can be very hard to shake.  Thus you can see elements of how the fellership got into the mess.

Joel had zero Reformation Bible, Westminster Confession, pure Bible type of background.  And he did not understand the AV perfection movement.  Joel was essentially miffed irritated that a person could believe that God had given them his pure and perfect word...tangible, readable. He even struggled to send me a supposed "error" or two in the AV, at the same time that he was saying that I could believe it was excellent and majestic (but not perfect.)

Blair Adams has always been stronger on these elements, but he did not stop the downward slide.