With the exception of S3 and S4, the finale is comprised of 3 people (S3 and S4 had a final 4). So the person above the yellow line would simply win the whole season.
Viewer's choice was a twist that only popped up last season, so it's not certain if it will happen again this season. Last season, we chose from the two people who fell below the yellow line when the F4 players weighed in. Instead of the two players who were above the yellow line voting out a person, the viewers did it instead.