Jesus did many things that we cannot do no matter how hard we might try to imitate Him - talking with Elijah and Abraham was one of those things.
Abraham and the rich man were both dead - one in heaven and one not. If the rich man was still alive you would have something here, but he was not.
Jesus calling Lazarus and the young girl back from the dead - see my first reply.
No matter how hard one tries, praying for the intersession of anyone who is passed is not Biblical. Please do not take this as a personal attack, we must fight against false teaching when it is encountered. How about we all spend time praying to Jesus to have Him show each of us the truth and to not rely on our own understanding, but on His truth.