in order to save special troops, you have to set a marker, have the special troops deploy separately from them so they don't lose supply and die. Then you have to move the rally point and use common troops, being able to separate men at arms troops just means you can save money when you don't need them
no reason you shouldnt be able to serch for people that will join your court as in a span of 10 years of game time you might had to serch for any number of people to fill jobs, evry time taking the long way to get it done, while im sure there are people out there with more game time then me i still have - 1550 hours in ck3 -
7860 hours in eu4 - 4625 hour in ck2 - and more in other Paradox games so let's wrap this issue up.