Conga Query not showing up on generated template document

I am new to salesforce / conga, so apologies if I use incorrect terminology. 

I am attempting update a conga template by adding some extra merge fields that utilize Conga queries and the Conga solution UI to automatically fill in some values. My problem is that when I generate the document using a custom action button on one of our record pages, the merge fields I just added are not filing in, so it leaves a blank space where the values should be. There are other merge fields on the document that work correctly, its just the new ones I tried adding that are not populating on the generated document. 

Here is the conga button I'm using (some Ids and names have been changed for privacy):

/apex/APXTConga4__Conga_Composer?SolMgr=1&serverUrl={!API.Partner_Server_URL_520}&Id={!SCMC__Purchase_Order__c.Id}&QueryId=[PurchaseProject]0Q_XXXXXXXXXXXX,[SSA]0Q_XXXXXXXXXXXX%3Fpv0%3D{!SCMC__Purchase_Order__c.Id}~pv1%3DContract,[InitialPayment]0Q_XXXXXXXXXXXX%3Fpv0%3D{!SCMC__Purchase_Order__c.Id},[FinalPayment]0Q_XXXXXXXXXXXX%3Fpv0%3D{!SCMC__Purchase_Order__c.Id},[SecondPayment]0Q_XXXXXXXXXXXX%3Fpv0%3D{!SCMC__Purchase_Order__c.Id}&TemplateId=0T_117UAM183313&SC0=1&SC1=SalesforceFile&OFN=Contract_{!SCMC__Purchase_Order__c.Name}&RM=1&datatagenable=1&DS7=11

And here is the query:

SELECT SCMC__Unit_Cost__c FROM SCMC__Purchase_Order_Line_Item__c WHERE SCMC__Purchase_Order__c = '{pv0}' AND SCMC__Line_Number__c = '1' LIMIT 1

And in the Conga solution UI, I added pv0 = {!SCMC__Purchase_Order__c.Id} 

Finally, in my conga template, I'm trying to access the value of that query with this syntax but nothing ends up showing when I generate the document:

{{InitialPayment.SCMC__Unit_Cost__c}}

Did I set something up wrong or am I using the incorrect syntax, etc? Any advice would be appreciated.  

Also, another issue I'm having is I'm trying to use a merge field to access a field on the Master object (Master object type is 'SCMC__Purchase_Order__c' using this syntax:

{{Master.SCMC__Total_Value_of_PO__c}}

But again, this value is not populating when I generate the doc.  

And as a general note, I know for a fact that these values do exist on the relevant objects. I have the record pulled up and am looking at the fields and the corresponding values.