When you look maven repo for those dependent jars at https://mvnrepository.com/artifact/org.jdom/jdom/2.0.2 you can look for the compile dependencies and check idle your aem or your Pom are using same version or different version

That means your dispatcher is not configured correctly. You need to debug on the dispatcher by setting the dispatcher log as debug and check what happens with the request 

Check request.log and access.log of aem publisher

So when you request page from dispatcher does the request going to aem publisher and if not then you might need to check the dispatcher rules for shortened url

I don’t see .html file extension fir the dispatcher url. Can you check with .html extension for dispatcher url as well or you have setup on dispatcher to work as extension less url?

You might not have permission to download the file at the location provided on cloud

1) In order for impersonating to work for non-admin users - even if member of the “administrators” group, the impersonator is required to have READ permissions in the /home/users path.2) impersonate will only work within the same group.

Check this articlehttps://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/unable-to-impersonate-in-aem-cloud-author-instance/td-p/580815

Do you have more than one publisher for your setup?i believe you need to change your implementation strategy, with HTTP session you might not be able to cache the HTML and best way to implement it via front end code like local or session storage and if you are not allowed to use this in your project...

No you can’t. Those are non- modifiable property