I would love to know what Andrew J. Robinson thinks of The Crimson Shadow. I would honestly spend non-trivial amounts of money to be able to discuss the book with him and Una McCormack (or even just to hear his thoughts).
Also would be particularly interested to hear about Brent Spiner's reaction to the recent developments vis à vis the Soong family (and his reaction to Light Fantastic). Honestly, though, I get the feeling he wouldn't be particularly interested. That man has an interesting relationship with his character(s), from what I can tell.
LeVar Burton has spoken publicly about being a fan of the show. When I saw him at a convention last year, he talked about having a minor geek-out when he's flipping through the channels and comes across an episode of TNG he hasn't seen before. (I envy him that.) Would that translate into interest in the books? Good question. With the exception of Indistinguishable from Magic, and I guess the early SCE books, not a lot has been done with his character. On the other hand, I could also see him enjoy the books simply because they're Trek.
I think that Avery Brooks would have strong feelings about where Sisko and Kassidy were taken in the books, but I'm not sure exactly what they'd be. Well, I'm sure he'd be happy about Unity. He was very unhappy with the suggestion from "What You Leave Behind" that Sisko would just disappear and never come back, so I'm sure he'd be glad that Sisko kept his word. Not sure what he would make of DRGIII's direction, though.
On the cover of one of the Vulcan's Trilogy books, Leonard Nimoy is quoted, "Fascinating!", clearly in reference to the book. Has he ever spoken about those books and where they took his character?