Already a brewery and some restaurants there.

2) Did the plumber just shut the building down, or was it coordinated with building management?

I spent many years in the restaurant business and I always tried to teach my employees to claim more tips for reasons you are experiencing, but the temptation of quick cash was generally too much. 

., area's biggest employer shuts down or moves, and as a result the tenant pool dries up, you could wind up going bust. 

There are 2 issues at play. 1) The buyer and 2) the appraiser.I'll focus mostly on number 2.If it's below grade, an appraiser is not going to include it in gross living area, and they aren't going to call it a bedroom, an ADU, or any of that (in the unlikely event that they do, you got lucky with a very liberal appraiser who gave you a gift, I'd suggest shutting up and not questioning it, hopefully the mortgage underwriter is having an "off" day and doesn't notice, but you certainly don't want to bring attention to it!).

It's in a walkable location to the lake, shops, restaurants, great for commuting (near freeway and bus stop). 

Please make sure the door is sealed shut".

Its a very wealthy and safe town, and this house is right around the corner and in walking distance from the historic main strip, shops and restaurants.

It's in a prime location and next to a thriving restaurant.

Lots of new restaurants and some very high priced single family sales been popping up in Bridgeport especially.