Oh yes there is. If he bought a "whole arsenal" to sell for a profit, then he is in the business of selling firearms for a profit which requires a Federal Firearm License. You are citing examples of ways to get around a law and I can assure you that the ATF is not going to considerdeliberately buyingguns for resalea hobby.
As for having the purchaser to "run a few rounds through it", that makes no difference in a straw purchase. You can play all the games you like, but the intent to go around the law is what is going to get you in trouble.
You can do as you wish of course and it is none of my business, but you are giving bad advice to others on how to get around a federal statute on firearms which is a very serious thing. You might get away with it and you might not, depends on if you are caught as with any other violation of the law. IF you are caught and the ATF can or does prove that you are buying for someone else who cannot legally buy, you have real problems. If you are are buying guns to sell for a profit without a license, you also have problems.