You cannot setup a team of dozens of people to run an important sector of the whole country by having them apply for positions. Not even companies hire that way, most companies hire based on recommendations and contacts. You don't have time for this, they need to form a government in a month or so. Six months in people already get antsy if enough is getting done, you'd be going through the third round of interviews.

Not every country has a spoil system, there's probably no need to change anyone in the institutions (except those very close to Vučić in dangerous positions)