Power of Attorney

What is the legal effect if I add a provision in my power of attorney that my three children must act jointly?
I wanna name my three children in a power of attorney of my estates in New Jersey. Can I execute a multiple power of attorney that gives them all equal power? What will be the legal effect if I add a provision that they have to act jointly?
Can an attorney-in-fact delegate a work conferred on him by a power of attorney to another?
My wife, who lives in New Jersey, executed a power of attorney so that one of her managers can manage her business accounts. This includes maintaining her finances and filing tax return. The manager delegated all those activities to an account management firm because he felt the tasks require special skills. Can he legally do that?
Is a banking transaction made by a bank under the authority of power of attorney is binding on the principal?
I am a resident of New Jersey. I wanna know whether a banking transaction made by my bank under the authority of my power of attorney is binding on me?
How to determine a compensation of the attorney-in-fact in the absence of principal’s direction?
I am an attorney-in-fact in the power of attorney of my uncle’s business. I wanna know whether my uncle can fix compensation to me. What will happen if there is no direction from my uncle for my compensation?
Will a subsequent execution of another power of attorney revoke an earlier power of attorney?
I executed a power of attorney of my estate in New Jersey to my niece. There was no mention that it will be revoked by a subsequent power of attorney. Thereafter I changed my mind and executed another power of attorney of the same estate to my nephew. Will the subsequent execution of power of attorney to my nephew revoke the earlier power of attorney executed to my niece?