What is the etymology of the Biblical name "Ishmael"?
Was this name ever used for any of the Biblical characters before Ishmael, the son of Abraham?
Genesis 16:15 tells you the origin of the name: Abraham named him that. Rashi explains he did so with divine inspiration, in which case God likely (IMO) implied the same meaning as he had in verse 11: "because God שמע, heard, your pain".
No Ishmaels prior to Abraham's son are listed in the Bible. (That doesn't mean none existed. Most people aren't mentioned in the Bible.)
And the angel of the LORD said unto her: 'Behold, thou art with child, and shalt bear a son; and thou shalt call his name Ishmael, because the LORD hath heard thy affliction.
So etymologically, the name develops from the Hebrew root "sh-m-a" meaning "hear" and e-l, god's name. Those roots, are then combined (in one of many possible ways) to create a name from word/ideas.