"And I love you too."
Translation:Và tôi cũng yêu em.
Và tôi yêu bạn cũng wouldn't be right? Also, when should em be used instead of bạn?
No, sorry, cũng has to go with a verb. You can't put it at the end.
bạn = friend
Em is a word we use to address someone younger. Traditionally the girlfriend is younger than the boyfriend, so em is always used to address the girl in a relationship. Anh is for the boyfriend regardless whether he's actually older or not. So technically it should be:
Và anh cũng yêu em.
But since it does NOT say "anh," em shouldn't be used, or at least not mandatory! Anh and em go together; Toi and ban go together. Since it has toi, BAN SHOULD BE ACCEPTED. IMO. Hon nua...since it doesn't specify Anh, it could just as easily be Va em cung yeu anh. Or Va me cung yeu con gai, etc., etc.
I think you are right, in the song he is saying all the things he loves so he uses tôi because he is not talking to anyone.