You want to start with the core of the language, which includes basic vocab and grammar, and in the case of Japanese, the alphabet. Hiragana should be your starting point since it is what the most basic words are composed with. Kanji only really becomes necessary when you start dealing with more abstract or intellectual concepts; think of it like all the Latin and Greek stuff we have in English.
As for learning from songs... I'd say it works (I've learned quite a few Russian words that way), but as for the English following it thing, if I were you I'd just find the lyrics (in English, romaji, and hiragana/kanji) online somewhere, print or write them out, and look at them as you listen. And do not actually sing them out loud unless you have a good voice and pronunciation or else it will sound terrible and create a public disturbance.
