If you are going for powerful girls for Harry then my vote though it may be unpopular is Ginny as a bonded. I'll explain despite Rowlings bad job in writing her in the story she did place Ginny as the seventh child and since in Magic seven is a powerful number maybe that translates to a powerful witch. Which would add to his power in fact since she is not well written in the series who knows what powers she may have that Harry can get.