From one newbie to another, it seems that your keyword phrases are a bit esoteric. When I read them I wonder if people will actually type those into a search. Your findings of low-to-no data in the keyword tool would support this.
"Niche" is good, but can be taken to an extreme that simply doesn't deliver.
Real estate agencies rely heavily on the Internet for their business. Consequently, the terms that work are highly researched and competitive.