Pipp song revealed in toy.

[Werewolveswithagenda 15]

I personally don't think it's a bad song. Not my taste but I think it's fitting cause if I am right, the pegasus characters are kind of like pop stars/social media influencers. 

[Splashee 28,537]

It has this annoying Pinkie Pie vibe to it 

[Lord Midnight Madness 1,542]

I think some pop songs are ok but I hope the show is not saturated with nothing but pop music.

[Truffles 2,033]

These songs are likely the songs Pipp sings during her various concert appearances and radio broadcasts and are likely just there as background ambience while the other characters are talking and/or doing things. These are unlikely to be part of any musical numbers. One of these might be used for the end credits, though.

Izzy's  song (if it made the final cut) is definitely a musical number, however. It is likely used during the part of the trailer where she's getting everypony to disguise themselves as unicorns so they can all get into Bridlewood without causing a panic.