1: Since they are official group working for the king, why not let's say use some guards or soldiers to check if the combat applicants have the needed battle skills, cause otherwise what's the point in sending the people.
2: For people such as the missionarry and the wandering priest just have them point out their good points such as the lore, medcince knowledge, etc...
^ there are some ideas, but there are a number more different ways it could be done also.