I’d also like to know the answer to this question.
You are allowed as long you provide the dev version too. You can name and use your .min files.
Minifying your JS files is just good practice. I don’t see why you wouldn’t do it. You’d want to add both a minified and un-minified version of the files though. Just load the minified version.
As far as the license goes, are you going to distribute this code to anyone else? If not, you don’t need a license. Licenses are only really useful when distributing code. If you are distributing the code, then you’ll most likely need to put it under an open-source license. But, that depends on whether it would be considered a derivative work under copyright law.