Due to her warmth, good looks and charm, Yingluk was, and no doubt still, remains popular upcountry, but I wonder whether she's ambitious enough to want to be PM again.
Plus her lack of political experience, poor English and geography skills would mean more criticism on social media.
I'd expect Pheu Thai to use her more for boosting their image, campaigning during election time, etc
But she may prefer a private life, after all Tony owes her a lot.