I know no theology
, but I might be able to clarify some confusion
of names. or make them more confusing...
'abaddon is the Hebrew word for 'destruction', from the verb 'abêd 'he destroyed'. It begins with the consonant aleph.
I have never heard of the angel Abbadona but it looks like it contains the (Aramaic) word 'abba 'father' (which gives our 'abbot'). However, I don't know.
The angel Abdiel meaning 'servant of God', contains the element &abd- from &ebed 'servant', the same as in Arabic names such as Abdullah. It begins with the consonant ayin (I'm writing that '&') and cannot be related to words beginning with aleph; not within the one language, at least.
Apollyon is from Greek roots, literary 'looser-off', i.e destroyer.
The Greek god Apollo is unrelated to any of these; it is not in fact a recognizable Greek name in origin; and there was a proposal in the controversial book Black Athena that it was an Egyptian divine name brought into Greek via Phoenician.
The Greek word abyss (or abysm) comes from Mesopotamian languages: the word is Apsu in Babylonian, and Abzu in Sumerian. He was the sweet water under the earth, the primaeval god, the first to be mentioned in the Babylonian Epic of Creation: so this name at least is considerably older than all the previous.
No doubt it was just as easy to confuse these in ancient languages, and that was done, as it is in their English transliterations.