A lovesick student turns down his dream-intership to travel to Hong Kong to meet his holiday romance, but after he loses his phone he has to figure out other ways of finding her within 12 hours before he flies back again. (Note: it’s a short film concept)

Agreed with Foxtrot25 and DPG, this has very low stakes.

Perhaps it's the shortcoming of the genre for someone like myself, but it seems as though,?to his own detriment, he's a hopeless romantic. His flaw appears to be that he's naive and lacks a sense of priority, does he change by the end of the story? Or does he remain the romantic he was at the start?

Well, I guess for a short it might play.? But, really, what's the urgency, what are the stakes? What's the worry?? So he doesn't find her in 12 hours, has to leave?? What's the loss?? Can't he always get another cell phone, get in contact, try again?

On the other foot, if he has 12 hours to find her and talk her out of marrying the wrong guy...

fwiw

Regardless of the length, what is the take-away after the audience views this? In other words, what is the lesson/theme. What's a Holiday love?

A short, even more than a feature, needs to have a take-away or else what's the point? Irony is king for a short scene, IMO.

I mean, is it such a life-changing event to find someone without our precious electronic devices these days?

The good is that you have a ticking time bomb and you have a goal. The stakes aren't so high/especially if she doesn't know/count on him even coming.

He doesn't know her address, btw.? It's her birthday and he wants it to be a surprise visit.