I think going in to the deal guaranteeing 80% is a bit of a bold step, but it really depends on the address and the neighborhood characteristics. 

It was around the corner from the main box, so I just stuck up a little note for a while that said "mail addressed to unit B should go in the box around the corner".

However, you may have to put these losses on layway due to the Passive Activity Loss (PAL) rules which are also addressed in my post.3.

Because the "2nd" is not addressed with monthly payments, transactions with a prior HARP are huge problems.

Are there ways to address this concern or to communicate the value of these unique features to the appraiser effectively—without overstepping?

As adoption grows, and I think it's going to be massive over the next 1-3 years (probably 2-3), we will see more hedge funds, pensions, and once we have an ETF - which is slowly getting closer as issues are addressed and bad players weeded out, we will see RIA's and other investment advisors get in for their clients. 

When you get your appraisal, post your appraised value and value of property without the ADU and ideally the address.  

@Karen Seguin, it all depends on what you are trying to convey to your tenants.At minimum, any welcome letter should provide updated contact info for maintenance requests and mailing address for rent payments, and if the legal notice address is different than lease, include that.This can also be a good way to politely remind people of any general rules that you expect them to adhere to.  

Google "nyc dob bis" and when you get to the website type in your borough, street and address.

In particular I am seeking help for the following;1) "Provide an evacuation plan (shall include Site address, floor plan//site map, escape route(s), meeting placeoutside the home, emergency number 9-1-1).