109 Montgomery Street, 12-Story Building Planned

So does this mean it's all market rate?

So far, yes. The developers have not accepted a rezoning in exchange for below market units. ...and the city has not announced that they have accepted a tax abatement.

Construction on this lot is underway. They are digging the big pit for the foundation. Occasionally they fill the pit with water, creating a giant pool. Not sure what that's about.

What kind of building/how many units was settled on?

12 stories, 163 units. http://a810-bisweb.nyc.gov/bisweb/JobsQueryByNumberServlet?requestid=2&passjobnumber=321090029&passdocnumber=01

163 units, all market rate. Jeepers.

When HPD and Deblasio are the highest bidder, developers are more than happy to build the affordable housing that they desire.

I assume this rendering supersedes the one above from October 2015

This new one is way nicer. Looks more expensive.

market rate in flatbush is often cheaper than 80% AMI 'affordable housing'