Private Server Clients - A few questions.

First of all, Thanks if you have even bothered looking at this, to sum things up: my friend and I have recently undertaken the task to establish a private server that all my friends can play on.
So I wanted to create a custom client. And I need a bit of advise. I don't have much experiance in Java, But I have knowlage of various other programming languages (PHP, HTML, CSS, VB6.0, C#, etc).
Basicly I've just come to ask a few questions:
-Should the client be completly written in Java. Or could I intergrate a
client interface into say, Visual basic? (Kind of how SwiftKit works, but
with a modified RS client).
-Are there any relieable open source clients, that I would be able to
edit?
-Do you think a web based client would be better than a desktop
based client?
-Is there anything else you think I should research into?

Thanks very much for the time you have taken to consider adviseing me and any feedback is much appreciated. ​

 

The client itself would have to be in java.

Yes really good ones, look in rune-server.org

Depends on how heavy it is, if you add a lot of custom items and code to your client(like item lists, mp3 player) desktop would be better.

When someone releases his server code, if its a good server it will usually come with a client, start on that would be easy since they are already pair up