PM and myself feel, based on the description, that this mold was probably tenant caused and that we should show up to survey the process a bit and provide tenant with information about mold and airflow, as well as a dehumidifier, and have them sign an addendum to the lease that they are responsible for any reoccurrence of mold that they create via furniture placement etc.

But essentially, you would buy the home with the double lot, then survey off the other lot, then build a home upon that lot. 

Because in surveys it is reported as an amalgam of markets over a huge distance.While Downtown appreciates at a rate of 10% a year or better, each neighborhood is different.

In terms of other expenses I didn't see on previous posts, be sure to remember any pre-purchase stuff (appraisals, surveys, etc) and certain closing costs or lender fees may be expensed.

With the now required survey up front, I could see people spending up to $10K before even getting started.Happy to discuss more.

Aren't the costs related to attorney fee, document fees, survey costs, recording fees, appraisal fees, etc. typically added to the basis of a property when first acquired?  

How confidant are you in the IAQ survey work?

This included land costs, permit cost, survey costs, construction costs (including GC fee), materials, etc.  

but from what I read for nation-wide real estate surveys, that's the case everywhere.

A survey should be registered with your land registry office.