I don't think this is realistically achievable when you have all kinds of distortion and echoes.
You'd also need a way to identify the exact position on the song and correct that if it was wrong because it was in the refrain.
You're right about echoes, but it doesn't need to be perfect - the echoes are already probably below the detection floor for the takedown filter.
Also: If you identify and match up with a refrain, you'd still nullify that refrain. You'd just have to keep on your toes and move to the right location once you realized there was a mismatch. This is a classic cat/mouse "warring filters" problem!