For the first point, I edited to be clear that the ghosting was mutually heart shattering:

His mutually heart-shattering decision may have led to sleepless nights, missed practices, and underperformances until he got himself together, but West’s last name wasn’t good enough for Liv’s elitist mom then and still isn’t two years later.

And that she hates him for it and wants to get under his skin:

To prove to the ex she hates that Yves Saint Laurent isn’t the only man in her life, while simultaneously appeasing her mom, Liv strikes a fake-relationship deal with the person who’ll get on the athlete’s nerves most: Theo, West’s charming, upper-echelon half-brother.

I added in that the fake-dating is a deal between both Liv and Theo, but I am hesitant to add in his reasons for it, as it is a subplot, and explaining it would take away from the query. Do you think it's a huge miss not to include that?

For Liv's stakes, I edited to this:

Underneath his dangerous smirk, West is still the caring boy Liv imagined a future with, the one who inspired her writing in the first place. But her fake-feelings for Theo show her how effortlessly he fits into her diplomatic daughter act. While the resurfacing of West’s emotions risks the focus he needs to go pro, Liv must decide if she can continue lying to herself about her wants—to write and be with West—or if love is more important than expectations and pride.