if you check archetype.properties file in your project you will be seeing details like below one - # Parameters used to generate this project with aem-project-archetype groupId=com.aem.demo artifactId=aem-demo version=0.0.1-SNAPSHOT package=com.aem.demo appId=demo appTitle=AEM Demo sites aemVersion...

As AEM doesn't have OOTB feature so I have explored user account lock with maximum number of failed attempts, you can see the details here -   https://medium.com/@debal.india2014/aem-author-account-lockout-feature-4741073bae6a   But in your case, you need to lock the account once that person leaves ...

I think you have referenced EcommerceResponse in your servlet using @reference annotation and EcommerceResponse is a POJO class right?   We use @Reference  annotation to inject OSGi service. As EcommerceResponse is not an OSGi service and  EcommerceResponse is not available in OSGi Service Registry ...

I agree with @Kiran_Vedantam here, we have content fragment and experience fragment features in AEM. Using these we can create content at centralized location and after publishing the updated content will be available across multiple sites.

  Just sharing one idea here if we do send required metadata of each asset to Solr for indexing and use this Solr search in external application.  Do you see any deficiency @arunpatidar with this approach? 

We use @reference annotation to inject OSGi service.   You can define your Util class as similar to https://github.com/adobe/aem-core-wcm-components/blob/main/bundles/core/src/main/java/com/adobe/cq/wcm/core/components/internal/Utils.java   Then call the relevant static method using Utils.methodname...

Is GetUserProfileUtils an OSGi service? How did you call GetUserProfileUtils in your servlet?

I have followed the steps and able to replicate the issue. I will keep you posted if I am able to find anything.

Could you please share the screenshot of user's permissions tab, it will help me to debug.

I feel if you add those users to OOTB content-authors user group as shown below then they will be able to use pick button as expected -     I have tested at my end. Please give a try.