Here's a slightly better formatted version of the query:
DECLARE @TicketNo            AS bigint        = NULL;
DECLARE @Group_Assignment    AS nvarchar(50) = NULL;
DECLARE @status                AS nvarchar(50) = NULL;
DECLARE @Urgency            AS nvarchar(50) = NULL;
DECLARE @Ticket_Category    AS...

And another with the same technique:
CREATE TABLE #Template (
    TaskName VARCHAR(20),
    TemplateName VARCHAR(20)
);
INSERT INTO #Template (TaskName, TemplateName)
SELECT 'Task1', 'Template 1' UNION ALL
SELECT 'Task2', 'Template 1'...

If you are going to do dynamic SQL, please do that in your stored procedure.   Don't try to do this in SSRS.   It's extremely difficult to troubleshoot, and a genuine...

This kind of thing should be handled in your dataset, as opposed to SSRS.   You can also make a parameter multi-valued, and use the JOIN function within SSRS to construct...

Use the JOIN function in SSRS and you can get a comma delimited list.   Just be sure to change your dataset to use a text query that adds the JOIN...