Well no i don't think so just because i guy has a shield and kicks people means nothing, also that is one of the most common shield look i find.
Are you playing a AR blaster?
If so, try and make the final shot a snipe shot....that would be cool.
Yes, I'm sure you can. Patriotic heroes are way too common in comic book lore to be disallowed all together. Just make sure he doesn't resemble a certain captain too much and make sure his background story is different. The background story you put in his description can go a long way to resolving the issue.
Edit: I made a new character myself who has a shield and uses fire melee (I already have an MA scrapper) and he has a very patriotic look with a star on his shield called American Daemon. His background just says "The most patriotic denzion of the Abyss you will ever meet."
Can I make a martial artist based EB with a shield who dresses up in a patriotic outfit with a patriotic name (without a rank or nation in his name) and not get in trouble?