No, Umbra, never ever fake a letter.  (This is with reference to the question you threw out at the beginning.)  If there is a subject that you know a lot about, on which you have done a great deal of research, and which would be of interest to many of your readers, but it seems not to be coming up in answers to anybody's questions, then you can do a couple of things:

Write a fake question, asking for the kind of information that you want to present; and in your answer make at once clear that it is false, there is no such questioner as Umbrella Darkover, or whoever, but you sincerely believe that the subject is of interest to at least some of your readers.

Come up with ingenious tie-ins to questions in genuine letters, as you seem to have done very nicely here.