Justin Weaver deftly combines catchy pop hooks with timeless country tropes. He introduces some romantic stakes to the late-night tailgate party on Brantley Gilbert’s rock-indebted “Bottoms Up,” and he builds a big, yearning chorus to power the sun-kissed nostalgia of Riley Green’s “My First Everything.” He can do straight-up Top 40, too, as evidenced by the swaying melodies of “Like I’m Gonna Lose You,” Meghan Trainor’s heart-swelling duet with John Legend.