The rule is that you cannot take control of an equip/spell/enchant that you normally could not cast. A Forcemaster cannot Mind Control Sosruko because it says "Beastmaster only", but she can Mind Control an Invisible Stalker because she meets the criteria of "forcemaster only".
Pet, Blood Reaper, and, Veteran status does not confer a "mage/school only" status, so its a legal target.