Derek, I love your writing castle dream. Having checked out the ones on your list, I love numbers 1 & 5 the best. They feel light and spacious whilst retaining the old. They also seem to have the kind of space you’ll need for the writing courses you’ll be entertaining.
BTW, I think you might need to update one of your links, as #3 and #4 go to the same page.
Good luck with your wonderful dream! Very inspiring!