The post supporting the front wall was continued into the basement with a metal post that rested on a new footing dug into the basement floor. 

I buy existing property that is zoned correctly and have added a unit - once by building on top, once by using an odd portion of the existing square footage and currently by moving a house onto a lot.

Let's say market rent in our area is $875 for a 500 square foot 1/1. 

I've seen GC markup from 50% all the way up to 200% at peak season.So very roughly if you're thinking of cabinets at about $250 per foot then your back of napkin estimate will be $250 * 14ft * 1.5GC = $5,250 for those cabinets installed for 1000sqft of living area.

It’s not a large spot but it’s a small 2 foot area.Thank you!

Apologies first for such amateur question: in new developments, when construction companies quote construction cost for "$ X/sf", is this number usually "the total construction cost divided by living square foot ONLY" or "the totally construction cost divided by total square footage of the structure, for example, including garage (sf that are not counted when selling to buyer)"? 

The foot print of the existing structure limits your ADU to 50% of that.  

In coordination with a pre approved lender, this is one way to drive eyes and foot traffic with an incentive that displays seller consideration.

You can easily obtain a "cost per square foot" range, for the appropriate type of construction you have in mind, from any commercial real estate agent, appraiser, and most mortgage brokers in the desired locale.If you want to put up a highrise here, it will run $300-350 per square foot, plus the land acquisition cost.

What I have done is the foot work the marketing is up to you.Also included is the PR's and Atty's address and fone#.