1: for plain windows I would go with Macrium reflect Free.
2: If the pc's need both then both...
3: All cloning software should have separate image and system drives. You dont put the image onto the same drive you are creating it from (makes an endless loop kind of situation) The cloning software and the image can be on the same drive.
Just a few cautions about cloning.
1: your system has drivers installed that are compatible with your motherbd. Cloning to a different motherbd may produce an un-bootable situation.
2: your system has a user on it. This user will need to be removed and a new one setup on each cloned pc.
3: you pc has its windows activation/authentication key probably already installed - this will need to be changed on all the cloned pc's and then re-authenticated.