This page might as well be subtitled "Peter & Company Foreshadowing," since only one of the incidents they mention has actually happened in the events of P&C as of the date of this page being published. The rest will happen in time, so for those interested to see how Peter and Tracy become rivals, this will give you a checklist to look forward to.
Also, speaking of Tracy's character, I feel I should take this moment to clarify her inspiration. She is yet another design in the roster who is directly based on a real-life counterpart (and even modeled after her inspiration, how she looked during our early college years), but unlike the others, the cartoon Tracy's relationship to Peter is purely fictional. In reality she is one of our best friends, and in fact was Whitney's childhood friend all the way through elementary and high school. During a brainstorming session for Peter & Company a few years back, I wanted to have additional antagonists for Peter at school, so the idea was tossed to introduce Tracy to fill one of those roles (she thought it was hilarious and was honored to have the role of giving Peter a hard time, hehe). This portrayal is, again, entirely fictional, as we have never been enemies in any sense of the word; she is actually one of the sweetest and most talented individuals I've ever known.
And, in fact, she and her girlfriend Yesenia even have their own comic series called Gemini Journey, which I cannot recommend highly enough. It is absolutely adorable and should definitely be checked out by everyone.
Thanks as well to the owners of the cameos featured in the final panel of this page: Metalhead0113, SorcererLance, KirbyCanvas, and Thwaites!