I'm not sure if it's as simple as this but you can to go to Analysis/Table Layout/Show Empty Rows or Columns. Select and that should by default show ALL available. If that shows too much you can limit with a Global filter as a Set will still display the exclusions with this approach.
I hope this helps!
Drag Employee, Project On To Rows and When You will Filter for Project A, you will Get all Employee with Project A and Total FTE.
That Should Work,
If That Will Not Then Use This as Filter
Lookup(ATTR(Project),0) as Filter
That worked, thank you!