Can you show multiple spouses on the main input display?
The answer is no. You can request a change to FTM
How do you move a child that is attached to the wrong parent to the correct parent?
Select the child and go to Person, Attach/Detach Person. You use Detach to detach the child from his parents. You may see the option to detach the person from more than one family. Make sure you select the right one. Go to the father and select Attach Child. Find the child in the index and attach him to the family with the correct mother.