Took a little time to reformat your code:

SELECT
  [GL_TransLines].[GLL_Account]     AS "Account"
  , [GL_TransLines].[Amount]        AS "Current Expenses"
  , [GL_TransLines].[COP_Period]    AS "Period"
  , [GL_TransLines].[GLT_TransDate]...

Changed my code some:

-- your exec: EXEC sp_executesql @sql, N'@SearchResultsSetID INT', @SearchResultsSetID, '@ItemNameInput NVARCHAR(100)', @ItemNameInput;
DECLARE @SQLCmd NVARCHAR(MAX)
        , @SQLParm NVARCHAR(MAX)
        ,...

This is how I would write your code that you posted.  I understand that you are putting pieces together, but I think this helps illustrate what you are attempting to...

Just curious, but looking at the execution plans for the queries populating the temp tables, is the DISTINCT actually needed?  The number of rows entering and leaving the sort operator...

One thing I noticed in the execution plan is the residual IO.  Actual rows is 321,374 but the number of rows read is 15,747,409.  Seeing this with four of the operators...

Well, the crystal ball is finding its way a round to other people.  Looks like Sue managed to find and provide an needed answer.