If you amend your query to read as follows then you will get records that have null values in the marker status
Code:
SELECT Requests.*, [Marker Info].[Marker Status], [Marker Info].[Date Created], [Marker Info].[Hold Date]
FROM Requests RIGHT JOIN [Marker Info] ON Requests.[Style ID] = [Marker Info].[Style ID]
WHERE ((([Marker Info].[Marker Status])<>"Completed")) OR ((([Marker Info].[Marker Status]) Is Null));
BTW, I did note that you are using lookup tables in your data tables. This is a developer No No. While Access allow this to happen it is not a good practice. See the attached and I suggest you amend your db.
http://access.mvps.org/access/lookupfields.htm
I concur with Orange's statement about PK's.
Alan