How is black zetsu telling a story about the brothers before he was ever made. It's hard to tell what truth an what's not. BZ shouldn't be telling the story because he wasn't there at the begining. Only after he's shitted out of Kaguya does his story an knowledge of them start. BZ wasn't around when Hogo had a sharingan so he doesn't know jack before his time. (stop taking what's said by him as the real story cause he wasn't there at the begining)
People seem so certain that Hogo never had a sharingan because the manga never said he did. That's alot of work that the creator probably didn't have the time for. (Hence why he let it happen in the anime)
The bijuu's where created an then placed inside Hogo until he was ready to release them on their own. (Remember he was a old man when he let them loose to roam)