Hi i really think there is good intentions on your post but it simplifies too much everything and you are wrong about the way you analyze melodies. Things are not as simples . Thats not because you use the 5 that it creates tensions .
If you are in a modal harmony the notes will be the same but the tensions won't be the same . For example if your song is in G Mixolydian what you call 5 won't be a tension but a resolution . More important than that is the relationship between your chords and your melodie . C is 1 but will be the fourth of a G chords and i don't think we'll consider your 1 as a resolution note.