Javascript library advice

I'm building a javascript library, and I'm so lost, I have an awful structure, I don't know the right way to structure everything, and many other best issuess...

1. whether to use es5 or es6 and what's the advantage of each..

2. whether to generate lib and why..

3. whether to write comments on functions explaining that knowing that no one else will see the lib...
4. what's the advantages and disadvantages of using many external libraries..
5. is it a good practice that if the library get large, to split it, like lodash.get and lodash.set
6. is there any chance that using external libraries will conflict with other libraries