They are all used except the last sentence. We don't say "핸요" or "핸" but just "해요" or "해". 널 사랑한다고 "-다고" is a verb ending to emphasize the speaker's thoughts or claims to the listener 널 사랑해요/사랑해 "요" is attached to a verb ending and adds the meaning of honor or gentleness to the listener. So, "널 사랑해요" sounds more respectful or gentle than "널 사랑해". 널 사랑하고 있어요/있어. "~고 있다 (있어요)" is similar to present progressive in English. So, it can be translated into "I am loving you".