This girl could sing. Don't listen to any of it now.....had to dig back into the memory archives, and that takes a heep bit a doin.
Since the original was live, only fair to compare to live version:
Natalie Merchant - Wonder (1995) E. Rutherford, NJ - YouTube
Miley is average at best. Have a niece who is near opera quality singer, and does weddings and the like. Guess it depends on what a person likes. Miley can take a back seat, for this poster. Her voice is flat, no range (just like daddy), and little harmonious representation. IMV of course.
Yeah, Natalie Merchant can sing. Funny you should mention her compared to Miley and label Miley as having a flat voice, since Natalie is famous for her flat voice, not just flat in dynamic range, but also tonality flat in the lower register, which is why she has to be very careful about the key she sings in.
Natalie is a contralo with the classic
dramatic contralto vocal range, weight, timber, texture and transitional points. She has an effective (natural, comfortable) range of D3 to E5 (2 octaves plus two half tones).
Miley is an alto but with a mezzo-soprano tessitura and weight, which means her vocal range overlaps that of a contralo nearly to the lower register, and extends midway into that of a coloratura mezzo-soprano. She has an effective range of E3 to A5 (2 octaves plus 5 half tones). So when you say "her voice is flat, no range," you really don't know what you're talking about. Might be better if you just say you don't care for her and leave it at that, rather than trying to come up with ways to deride her.
If your niece is well trained in music, she should be able to instantly recognize the basic vocal type and range of any singer after about three notes, just from the tessitura and timber of the voice.