You should then replace ISCHILDNODE function with ISDESCENDANTNODE (s,parent)

Check all the conditions in the query again. I think parent.[hideInSearch] should be s.[hideInSearch]

Check all the conditions in the query again. I think parent.[hideInSearch] should be s.[hideInSearch]

Try the below SQL 2 query - SELECT * FROM [cq:Page] AS parent INNER JOIN [nt:base] As s ON ISCHILDNODE(parent,s) WHERE ISDESCENDANTNODE(parent,[/content/x/y]) AND (CONTAINS(s.[cq:tags],'ABC DEF^600') OR CONTAINS(s.blocktitle,'ABC DEF^400') OR (s.blocktitle LIKE 'ABC DEF%') OR CONTAINS(s.bodycopy,'AB...

You should encode the page name before using it in the URL. Check the following link - http://stackoverflow.com/questions/10786042/java-url-encoding-of-query-string-parameters

Try the following query - http://localhost:4502//bin/querybuilder.json?p.hits=full&primarytype=nt:unstructured&path=/content/data/masterdata/program&property=programName&property.value=marketing&property.operation=unquals&p.limit=-1

Have you written a custom javascript code to send the token as part of your AJAX request ? I guess the default CSRF javascript does not inject the tokens in AJAX calls. If you have written custom JS code then make sure to refresh the token periodically after every 5 minutes before you send the reque...

Have you verified that Webdav is enabled ? What do you see if you directly hit the following URL in the browser ?https://localhost:5433/crx/server

Yes it is a binary property. You need to create a package containing /etc/key node and install it on all of your AEM instances. 

Have you replicated the crypto keys (/etc/keys/hmac) in all of your AEM boxes as mentioned in the below doc? https://docs.adobe.com/docs/en/aem/6-1/develop/security/csrf-protection.html