Yes of course you need to provide evidence. We can't take action based upon claims people make. Please provide the additional evidence and a screenshot of his Skype ID.
Even though I never tried it and I'm not sure what kind of website you want to create, it's definitely possible to do it in Java but I think PHP is more commonly used for a reason, it's more effective and probably more efficient as well to do it in PHP/MySQL.
It's because they use 3Dsecure, no need for it to be safe because they're insured. @OP definitely use PHP with the MVC model and make sure nothing like sql injection is possible. You should start with setting up the server and your database.
These are just account usernames available for transfer so it's not considered account selling and thus is allowed.
@OP Gl, you got some nice usernames there.