Here's what I did. I had two different version of my game and I wanted to see if I could resurrect the two ghosts I had in the game.
In one of the versions, the two ghosts were playable members of the family. Andrew Millis, who was a level 10 cook and prepared the meal, was not hungry and refused to eat it at first. When he was hungry, he gulped the ambrosia right down! Grandma Millis ate it willingly b/c she was hungry.
In the second version, the two ghosts had been ghost-o-tronned and then I sent them to the Netherworld to make room for Sandi French who my Sim got pregnant!
So, I wanted to see if I could bring them back. I built a closed room (no doors or windows) with the family fridge, a table and two chairs and I put both of the burial urns in the room.
They appeared on consecutive nights. Grandma first (she died first), I put the plate at her feet and she ate it right up. Andrew sat and played games on his Laptop for a couple of hours and then gave in and ate the ambrosia. The resurrected w/o a hitch though.
I was stressing out trying to get people leveled up in gardening and fishing, trying to get the ingredients and then I remembered that I had a separate game, the Leah family, that included none other than Christopher Steel (who was level 7 at the time he married Kamber! She already had Life fruits growing in her garden (with the sprinklers left on continuously!). I loaded Kamber's "pockets" with deathfish and Life Fruits and then clipboarded her to the Library in "edit town"! I sent her into the other (Millis) game as a messenger. I used testingcheatsenabled true, then I held shift and clicked Kamber, and added her to the active household.