If I couldn't give Jonathan Tammy back, I'd give him and Sarah at least an entire evening with Tammy so they can experience a few moments of the family they could have been if she hadn't died. (If they could do it with Nadine, Sarah and Jenna in the Inside the Light episode it could happen again)
Reva a bunch of new red clothes since she loves the color red.
For Phillip a bunch of books for inspiration and a new laptop or fancy pens and paper so he can write the great American novel when he's ready.
Lizzie I'd give her some fancy perfume.
Bill some cooking lessons so he can spoil Lizzie.