I think the star rating, as with players, is there overall rating.
When searching for staff I look at individual attributes far more. So for a Scout, look at JPA JPP first off. Then Adaptability if you are sending them to places they aren't familiar with. If you want someone to report on opposition teams then Tactical Knowledge is also useful.
For Chief Scout I also look at Man Management although I am not sure if it makes a difference or not.
In the search criteria, set minimum levels for the attributes you need rather than a star rating.
As far as seeing a Manager in the list goes, it is unlikely he will leave management to be a scout, but could be worth a try - if you are a far bigger club than he is at perhaps. Offer a contract and see the job interest in the top right hand corner.