Yes.  Author and Publisher do not belong in the table shown.  I strongly doubt Edition or Media belongs there either.

I'm not sure about Date.  I'm not sure how...

;WITH cte_dates AS (
  SELECT t.*, dates2.*
  FROM temp t
  CROSS APPLY (
   SELECT
        MAX(CASE WHEN row_num =...

You'll probably get exactly the same execution plan either way.

But for ease of clarity, coding and maintenance, I'd write it this way:

SELECT sf.org,...

Again, the easiest solution is to simply split into two tables.

You can even keep the original table name if you:
1) Create the new table, with all the...

I don't know about "broken", but if you "uncluster" it normally, it runs fine.

And, yes, then you have two servers each running a single, separate, independent instance.

Somewhat confusing:  "has ... active-active, active-passive setup".  Huh, can't be both at the same time, which is it?

If A-P, I know we've undone/removed clustering and it worked fine,...

Difficult to tell exactly what you need, but if you want the other conditions to apply to "Developer" too, then do this:

WHERE (customer = @customer_number)...

Use CAST (it's ANSI-standard), and CAST the final result as well, if you want a specific size of result:

CAST( CAST( SUM(Principal1) AS DECIMAL(5,2) ) + CAST ( SUM(BankInterest) AS DECIMAL(5,2)...

See if this gives you what you need -- it should at least be very close.  Btw, T-SQL isn't like C#, you don't need separate statements for every calc.