Just to clarify, I don't know officially that HTML and the rest of the formats that FBReader supports will be in the new firmware. The only details provided to me so far are the two quoted items in my original post.
I would assume that Ectacto would not remove such functionality while porting the program to the Jetbook. We'll know "The Shape of Things to Come" in a few weeks
I did email Ectaco a few more suggestions about integrating FBReader into the Jetbook. I hope they find these suggestions helpful and not consider me a pest.