As the Article notes, such a trend is not a sign of a Healthy Marketplace.

90% LTV HELOCS on investment property-TD Bank advertises this (technically 89.9% is advertised)90% LTV HELOC on primary residence-US Bank advertises this, obviously TD Bank would do this too.Otherwise, the only banks I've seen offering 90%LTV HELOCs on primary residences are local credit unions in my area (Direct Federal and MIT Credit Union).

Is there anything illegal about doing one business and advertising another?

The fact that the working class hourly wage is not following the appreciation trend is a significant concern. 

The goal is to not get too fixated on any one month or one data point, but to ensure the long term trend is headed in the right direction.

But that has no bearing on your advertising it 3 bedroom with egress- cost between 600-1000

According to my CPA, we can't deduct it yet because it must be "placed in service" which means it is advertised AND available to rent.

We still have yard signs but some houses don't lend themselves to drive-by advertising as the roads are secondary. 

Specifically in NYC there is strategic value in having offices due to the advertising and financial industries. 

If it's a flip, I'll do whatever the trend is, if it's a rental, I'll do whatever is most economic.