Well, on 1st glance of this list you have provided, I must say, you've covered quite alot of intresting ideas/visits.
I think one thing that may be good for us living in the UK (or anywhere really) is to find out about travel to Japan.
For example: Would the traveling cost be included in the travel package? (e.g. plane tickets)
Will you have a representitive meeting us in Japan or UK? If so, which airport?
If I were to go, I would like to go to places/do things you can only find/do in Japan. Of course there's the anime/manga visits that are a must, but I would probably like to see the traditional things. E.g. Kabuki, shrines, sumo, Tokyo Tower etc.
I would also probably like to go to the Eastern/Japanese style accomodation, but I'm not so good with my Japanese (as others may also be.)
My only suggestion is that we could also visit a Hot Springs, like in most manga. Unless the hotel/accomodation has it's own, then it would be a big plus to the package.
Hope that helps. *Bows*