Still here...
Sorry for the confusion. The structure (not guest house) has two levels and it's attached on one side to a large garage. There is no kitchen (borrower tried putting one in and was denied) and one bath on each level.
I've been reading every post in this thread, and I see most responders struggling because your original post, and most following posts, are all confusing due to typos and poor wording, as well as a lack of clear descriptions. For example, you've still not bothered to describe the floor plans of the extra buildings. We just, at the post of yours I am quoting, finding out they have bathrooms. Well, what about bedrooms, separate living rooms, heating and cooling, etc? What quality level of finish do they have?
An additional problem going on in the thread, and I strongly agree with the prior posts stating terminology has been a mixmash, is inconsistent use and definition of the labels being used. You need to recognize that these labels do not have consistent meanings all over the U.S. and that you are asking for help from appraisers all over the U.S. One small thing Dennis was questioning that I can probably clear up, and that is "why does documentation refer to "Guest House" if kitchens are prohibited?" First, I assume that somewhere in your area there is some sort of jurisdictional authority that defines what a "Guest House" is and has defined one as something that requires a kitchen. If so, what has probably happened is the local assessors office, required to reflect all improvements to achieve taxation purposes, had to use some sort of code for the improvement for taxation. The best available code the staff at the assessors office had to use was "Guest House." Hence, a tax card showing a guest house as the assessors office does not have to follow building code or zoning in the use of codes created (who knows when) for taxation purposes in getting a mass appraisal model to work.
P.S. Decided to edit my own for possible clarification. You all have Prop 13. The tax codes on some old assessors characteristics card created for taxation purposes could predate Prop 13 and that could possibly be something that might cause confusion. Generally, I have the impression that no assessors staff have been to this property in a long time perhaps?