You can quickly write a small fiddle script using ACS tools without adding this code your source repohttps://adobe-consulting-services.github.io/acs-aem-tools/features/aem-fiddle/index.html

Did you followed these two documentations for package inclusion:-https://adobe-consulting-services.github.io/acs-aem-commons/pages/maven.html https://github.com/Adobe-Marketing-Cloud/aem-core-wcm-components#include-core-components-as-subpackage-into-your-own-project-maven-build

You can use ${request.requestPathInfo.suffix} to access suffix in HTL

Can you enable Content Fragment Model from configuration browser and again apply that config to your path This link will help you to do ithttps://helpx.adobe.com/experience-manager/kt/sites/using/content-services-tutorial-use/part2.html

Would have to override that file in /apps

Was this encrypted by the same publisher which is decrypting it?If you have multiple publish, make sure those are using same keys.

That option is available in the context  Jörg  has explained

You can use ACS Commons Query Packagehttps://adobe-consulting-services.github.io/acs-aem-commons/features/packagers/query-packager/index.html

Your first URL goes towards selector implementation in AEM, Look at the complete guide here https://helpx.adobe.com/experience-manager/6-2/managing/using/seo-and-url-management.html

The one you are referring is the summit lab session given by folks on 6.3.https://helpx.adobe.com/experience-manager/6-2/sites/deploying/using/best-practices-for-queries-and-indexing.html