Interesting thought. I personally think that there is somewhere that our spiritual energy goes. While I am not an overly spiritual person, I feel that as humans we do possess a certain spiritual energy. Ever notice that the mere presence of some others can make you feel great or bring you down. I think that when we pass, our energy goes to another place to exist. Somewhere many refer to heaven although I don't think heaven exists as a physical space.
That is why we hear so many stories of people having out of body experiences or encountering spirits (energy), good or bad, that are for some reason, still present on this earth. That may explain why people throughout the ages have reported seeing or being visited by angels or other entities for "the other side."
As to our loved ones, I don't think their spirit takes on only one form. I think we will see them as we remember them and they will see themselves as they wish. My grandparents might see my Dad as a 40 year old man and he would see them as in their 70's when they died. Or he may see them as vibrant 30 year olds as they were wehn he was ayoung lad. They might see me as the 6 year old boy they remember while my grandkids may see me as a 80 year old man (if I make it that far, LOL!).
I must admit my biggest fear is after I die, not having any connection to my daughter (and grandkids, God willing) for the rest of eternity.