I just hope Harry won't be too whiny about it :P "Oh Mama, I've finally found yu! I just luv yu so much! ... HOLD ME!" But yeah he'd light up like nothing we've seen, at least if she's a conpassionate person. Imagine that, a parent that actually is nice to Harry! If she had been there maybe he wouldn't have endured all that crap. I'm pretty sure he'd accept her right away, not even considering/caring that it might be his dad trying to mess with him (which it isn't but Harry should not be trusting his dad ever). And she could meet Normie!
This is actually the first I've ever heard of Emily but yeah exploring her would be tons of fun.