Whew, I see I'm not immortal! I think mine fell under the almost-got-it-right category. Here's what I sent:
"Ooh, ooh, I love this!

"Words that are words but can become other words when a letter is added to the beginning"!
(rotund---> orotund)

Oh, how awkward that was, but I don't care! Can't wait to find out the theme! :-)"

When the last word came 'round, I sent him:

"If beheading is what you call it when you take a letter away from the beginning of a word to make another word, what do you call it when you add a letter at the beginning to make another word? :-))"

No answer.