Uhm if I understand you your question is about making a server for yourself ...
If you are able to do that... which involves alot of coding I guess.
You are able to kill monsters, if you program them to spawn. You are able to raise stats if you code it yourself. And yes you can summon your own items.. IF you are able to code them..
So if you can code your own private server, you can do those things to.
But I doubt if you can code your own server