Balanced: 40 Earth/ 36 Cold Earth: 40 Earth / 24 Cold Air: 45 Air/25 Cold/10 Earth or 45 Air/ 29 Earth (47 Air/ 26 Earth) Each build has own advantage depend on your play style. So, choose the best one for you.
Resist rate is the difference for ice pets. Basically for the bottom lvl 50 they are more for constant interrupts and some dmg, the higher level ones land more often. But theurgs are about interrupts more than dmg.