Just finished hearing the entire panel. For clarification to people out there reading this, Uncle Deadly voiced the role of the Ghost Host from X Atencio's original 1968 draft of the attraction's story, as well as supplying various sound effects when needed (or not as the case may be). The narration also featured Kelsey McCullah (SP?), X's granddaughter as the Medium, the precursor to Madame Leotta; and the character Sally Slater (I suspect Jodie Benson's voice though I'm probably wrong) as the script's main narrator.
Haunted Mansion or casual Disney fans may know Sally Slater better as either the "Parasol Girl" or "Tightrope-Walker Girl" from the Stretching Room portraits. The interesting thing is Disney using the name Sally Slater for the character's appearance since that name comes from a poem/epitaph written by fellow mansion dedsident Prudence Proofrock. The character from the Stretching Room portrait has also been known by the names Daisy De La Cruz in the Slave Labor Graphics Haunted Mansion comics and/or Lilian O'Malley or Master Gracey's first wife in the Ghost Gallery backstories regarding certain others of the Happy Haunts.
Regardlesss, I applaud Deadly's performance during this presentation.