The reason why I did a second prediction because I saw that people claimed they see a faint outline on Seven's silhouette in Six's light antenna on the last second before it changed to the "7 be contined" screen before rolling the credits and fanarts. Then in between @PidiAmo and @FHZTheLorist_D-Z-S's conversation she thought that 7 would somewhat resemble a crocodile like how F does. So I came out with this.
CREDITS: Mike Salcedo for Number Lore. NOTE: Click on Seven to see what I think they would sound like.