Hi Ahmar,
1 - Same server.xml you've been using on your previous "web application" from past posts will work.
2 - Since you will be in a remote machine, you can use a client.xml, as you were trying to do from the previous web application but that was not working because you were in the same JVM as your server.
3 - You can reuse the same client.xml from step 2. Just remember when you instantiate the clientCache to give it different name, so you can see by the logs entries which belongs to each client.
Bundled with a Gemfire distribution you can find a SampleCode/quickstart folder that has a bunch of examples (code and XML) that you can freely use. Search for a Client.xml and Server.xml and refer to that to base your POC.
Hope that helps,
~/William