I can kinda tell that the writers made sure characters like Courtney, Bridgette, Owen, Heather, and Duncan had a lot to sing. Probably because they had some of the best singing voices and unless I'm mistaken I'm pretty sure both Courtney and Owen's VAs are also singers but I could be wrong.
Its actually interesting to see the comparison between the amount of songs started by a specific constestant and their control/influence Sure I dont have to explain Heather and Alejandro Bridgette is one of the hosts of the aftermath show, so while not having/having minimal influence in the game, she does have a decent amount of control in general Courtney caused the votes to constantly be split during the later half of Team Amazon. In fact, this also cross over into the other team, at least for one vote!