The Book of Enoch lays claim that the dead half human - half angels from the flood of Noah... are spirits who are not yet in Hell. And, they are demons.You already said that.
It's in the meaning of the words. Both words mean messenger/delegate/provider which is a description of what they do, not what they are. We have come to use the words to distinguish between good and bad spirits. Angels and demons are both spirits in nature, either referred to as evil spirits/demons Lk.2:8 or ministering spirits Heb.1:14 in scripture.
What is it with people nowadays that they can't tell the difference between a statement and a question? You've given nothing to uphold your position other than a vague claim and I'm wondering what you are on about. I haven't made anything up. Look up for yourself the meaning of the words angel and demon and you will see what I said was true.
What can be known about God from creation is limited to His Godhead and His eternal power Rom.1:20 so trying to derive answers to complex questions would be somewhat foolish in my book as the creation is not designed to answer them.
So, what then? We throw out tradition? Again you give nothing except make vague claims.
If you have an argument proving demons and fallen angels are two distinct species then put it forth logically and systematically and we can look at it. Otherwise, why should I waste time arguing against the air.