In actual fact, it is believed that the elders are appointed by holy spirit because they are judged to have met the standards for older men in Timothy and Titus. It is these standards, that the Society believes are from the holy spirit. Thus when a man is appointed elder it is because the elders and co have judged him as meeting the inspired standard in the Bible and thus it is said he has been appointed by holy spirit.
As for Judas, though Jesus knew his heart that did not mean that Judas was predestined to betray him. Judas did what he did because his heart was greedy nothing more. A business owner may know which of his employees is likely to steal from him but he says nothing until the deed is done. Meanwhile that employee enjoys the same benefits and pay raises and yearly bonuses of all the rest. So too Judas benefited from seeing what the others saw and hearing what they heard and eating what Jesus provided but that did not change his heart.