I've learned that hero could be translated as:
Aside from ヒーロー (which seems just to be roumaji version of hero), is there any usage difference among them?
英雄 is most normally used for heros whose status as such is established. ヒーロー implies an American hero. For example, Beethoven's third symphony is called 英雄 in Japanese, but no one would call it ヒーロー. 勇者 means someone who is brave, and is not the same as hero. 傑士 is not normally used.
Japanese hero shows are called 戦隊もの, as it comes from the early hero shows like 秘密戦隊ゴレンジャー, 電子戦隊デンジマン, 太陽戦隊サンバルカン.