null vs empty string

I have the following query:

SELECT * FROM "sales_projects" WHERE (((sales_projects.prospect ILIKE E'%rancho murieta%') OR (sales_projects.prospect_type ILIKE E'%rancho murieta%') OR (sales_projects.application ILIKE E'%rancho murieta%') OR (sales_projects.project ILIKE E'%rancho murieta%') OR (sales_projects.city ILIKE E'%rancho murieta%') OR (sales_projects.state ILIKE E'%rancho murieta%') OR (sales_projects.project_status ILIKE E'%rancho murieta%')) AND (((sales_projects.project_status != E'Dead') AND (sales_projects.project_status != E'Ordered')) AND ((sales_projects.status IN (E'Active',E'Expired')) AND (sales_projects.kind = E'Project'))))

Yes, it is ugly, but that's not the issue. This query returns just one record when I would expect it to return two. The only difference in the two records is in the sales_projects.project_status field. One record has an empty string, the second has a null value. The NULL value in sales_projects.project_status is not returned.

Can someone explain why the NULL value in sales_projects.project_status field does not fit this query?
Secondly, can you offer some advice to EXCLUDE records where sales_projects.project_status is Ordered and Dead?

Thanks a million for any help.