It is also currently not possible to possess a familiar and have mage hand summoned at the same time. However, as mage hand unsummons the familiar, it means the player would require using another spell slot to “resummon” the familiar. Perhaps it would be possible to give a second button that appears similar to the way that Disguise Self and the Speak with Dead amulet work, allowing you to “dispel disguise self” and “recast speak with dead”.
Seems a little overcombinated, concidering the fact that simply "allow to have more companions of different type" would resolve not just this, but some other (like Ranger) problems aswell.