Was Mr. Endicott voiced by John Cleese?
Yes
Thanks, I thought so...I love him!
He is also voicing Adelaide.
I noticed that! Reminded me of his days on Monty Python and all of his lady characters.
They probably gave him an extra role as compensation for flying in all the way from England. He did a fine job, though! "DO NOT WRECK THIS GIGANTIC DOOM."
I'm sure you've noticed by now, but I thought it was pretty cool that they also got Tim Curry to voice Auntie Whispers! If it's been fifteen years or more, it's no longer a spoiler.