Learn English – …so beautiful eyes.. Grammatical

1) and 3) are OK and sound fine. I won't comment on whether wide or big is better, as that would depend on the subject and opinion of the writer. Though I think big would probably be used more often.

2) I would use bug-eyed, though this has a negative connotation and could be insulting. In any case, I can't see that any term describing such a condition would be taken positively.

4) He is very wide-mouthed.

This seems like you are describing him or his behavior, rather than his mouth. Something like:

He is very open-mouthed (talkative).

But I doubt you would normally hear a phrase like 4).

The phrase you're looking for is

Music to my ears.

a welcome sound to someone; news that someone is pleased to hear.

A: Here's your paycheck for this month. B: Ah, that's music to my ears!

You could also say something like:

Being back at home and hearing the children laughing was music to my ears.

The purring of my Mustang's engine was music to my ears.

I went camping for the first time in years and hearing the sounds of the forest was music to my ears.

You can also turn it into a simile by adding like.

It was like music to my ears.