Unfortunately you can't achieve what is intended.For security purposes, any string / variable used in a query is automatically escaped.You can't use a single input string and use that in an "in" statement. What you could try is:bring in the comma separated valuesThen use a condition like ',' + ($(vars/@ids)) + ',' LIKE '%@name%'Though note that this won't be able to use any DB index, so shouldd be used with care

When do you see the discrepancy? During send preparation?Then you could check the delivery details.Just click on the "..." and check the tab "Exclusion Causes" which may show which rule excluded those addresses

With the dynamic editor, you can add any "available" field into the link URL.If you need any computed fields not stored in the DB, you need to use a workflow to compute the value. Then you can use it in the editor and can add it to the link