Ah authenticity. The way I see it, any submission not from a "girl band" automatically goes to the bottom. And that does gets ranked on the merits of the song. So it's not a matter which, "Which is the purest girliest band?" but rather, "Which is the best song by a girl band?" Does Heart qualify as a girl band? Also, this is Heart circa 1976, which is very different from mid-80s Heart, or even Heart today. If it's the debut single by band fronted by two sisters, where one co-authored (how much? who knows?) the song, and one's lead guitar and the other the vocalist for the song, where they at that moment a girl band? Does it matter that they since wrote other songs and performed songs that they had others write for them?
I'll just say this, if "Will You still Love Me Tomorrow?" was co-written by Gerry Goffin and Carole King, does that take away from the authenticity of it being performed by The Shirelles (none of whom even play an instrument)? I am the one who submitted the Heart song, and I stand by my submission for better or worse.
Typically I wouldn't defend my submission openly, but since people have been openly discussing whether it should even qualify, I felt I had to.