Answer: Reincarnate
Interestingly enough, even though they have literally gone to "hell and back" to be together and reunite with their children as well, Chris and Annie chose to reincarnate on Earth. Chris states, "I found you in hell, don't you think I can find you in Jersey?" Since they are soul mates, they have no problem meeting up again as young toddlers.
God is never introduced in this movie. Chris does ask Cuba Gooding Jr. (believed to be Albert and later found to be his son) where God is in "all of this", referring to heaven. Albert responds by saying, "Oh, He's up there. Somewhere... shouting down that He loves us. Wondering why we can't hear Him. You think?" I took this to mean that God is a benevolent energy force that binds all living things together and does not intervene in the lives of humans, since they have free will. Once humans leave the Earth plane and realize that thoughts are reality and that they could become "creators" themselves, they realized that God and they were one and the same. Of course, this is open for you to interpret it, as you will.