3. All in all, would it be worth to have my entire team be all Americans if I am from the USA in regards to merchandise income?
¿you mean from Chile, Uruguay, Mexico, Brazil, Canada, Cuba, Peru, República Dominicana, Paraguay, Bolivia, Argentina, Colombia, Ecuador, Barbados, Guatemala, Jamaica, Venezuela, or another American Country?
Well, the answer is no, but if you have an entire team with players of USA, then the answer is yes.
It's more effective if you train your draft players and they lead the team.