Of course Jesus has all power.
However, I did not refer to His power, but rather to His conduct. Jesus lived a perfect life; He is our exemplar. If we are to go where He is, we must take up our cross daily, and follow Him.
So, if Jesus thought it was acceptable to converse with righteous men who have passed on, I think it is probably permissible for us to do so.
I do not seek such conversations; I have never had one. But if God were to send me a messenger, I would pay heed to what he had to say to me.
Really, first time I've ever seen a mormon wanting to have anything to do with the cross.
And if SATAN sent you one...