The letter to the Hebrews, whoever wrote it, was probably written around the end of the first century. You may claim earlier, but I would wish to see proof, and anyway the later the better if you are going to claim some extensive organizational arrangements.
Even around 90CE the churches would have been little more than House Churches, what evidnece is there for more ? So, the "leaders" who are referred to would be Apostles if any were still alive, and those taking the lead in establishing the congregations that existed.
I am at present doubtful that to base ones life now on what was written 2000 years ago is a good idea in a literal sense, but if you are determined to do so, I can see little for you to dobut to join the smallest group of Chrisitans you can find who stick rigidly to the Gospel that Paul preached, as he hinmself said to the Galations:
"it doesn't matter if that person is one of us, or an angel from heaven, I have said it before and I will say it again, I hope God will punish anyone who preaches anything different from what you have already believed". Gal. 1 v8&9 C.E.V
Now, Paul wrote the above words around 55CE it is estimated, so the teahing at that time was the simple Gospel the first followers of Christ took to unbelievers, nothing more, so beware of groups you wish to join who add to that simple message i.e "Christ resurrected".