I would take a different approach.  Your two queries are very similar.  Rewrite your query to pull any record that would meet either criteria and then use two CASE/IF expressions:...

I actually prefer using the first of the month to group dates. 

• There is a fast way to determine the first of the month for any date.
• You can...

You can simplify this by using a different default value for the lag function.

WITH LAG_DATA AS (

    SELECT
        TT.rn,
        TT.dt,
        TT.[status],
       ...

You can also use TRY_CAST() or TRY_CONVERT() to identify which records have issues.  Each of these will produce a NULL value instead of an error when the conversion fails.

It's not quite in the format you asked for, but it can easily be tweaked.

CREATE TABLE #Customer_Balances
(
    Customer_ID        INT
,   Cur_Balance        MONEY
,   As_of_Date       ...

I see nothing here that argues for a dynamic approach.  Post sample data and expected results, and we should be able to help you come up with an approach that...

You also need to specify the logic used to determine which values appear together.  NOTE: Tables represent sets, which are unordered.  The display order is not a valid option.

Excel does not have a NULL value.  It has a BLANK value which is equivalent to ''.  When '' is converted to numeric, it is converted as 0.  You may...