Claim down. Everything you are doing is correct & legal. You can resell anything, that is just good business, that is what all those stores do, they buy it from some else who made it and resell it to you.
You can change it & it becomes yours are it is now unique in nature & resell it no problem at all. You can & should call the new pieces your own because they are. If you need to confirm this, there are 2 simple ways.
1-patents, part of the acceptance of a patent (new invention) is improving on a existing item. 2-lawyers, you can find on craigslist or just ask around a lawyer that will give you a free consultation about your questions, have them written down so you do not forget anything. It is great to see a creative entrepreneur, keep doing what you are doing, the rest will fall into place.
Best of Luck.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.