Well if we burn Madril, then it is evident that we need
Aragorn, ROTN to spot for the second levels, So he's necessary. Burning Gandalf works too...killing him, pulling out stronger Gandalf,
Sent Back, and either
Roll of Thunder or
Deep in Thought.
Sméagol,
Always helps can work out on his own...3 copies of
Don't Look at Them will come out anyway. Depending on what kind of shadow, we can choose to beef up Isildur with Narsil and all his artifacts, or choose to pull out even stronger Elendil and play Narsil on him.
For the time being, Denethor is useful for a number of things. He can filter the deck, so using
Saved from the Fire to pull him, Aragorn, and Andúril out, Denethor can pull out fortifications or other weapons we would need.
This is very general and probably is only scratching the surface of the variations that can be tried.