You get +1 internet points for calling it a "local server" instead of an "offline server". Most people wrongly use "offline server" to say they're using it locally.
You get another +1 internet points for using git instead of a downloadable package from someone else.
There are many many clients you can use, it's just upto you which features you want. I'd start by having a look at the diff'able clients here https://rathena.org/board/forum/99-client-releases/ first, or if you want to use an older one, they're attached to the "2015 clients" thread under Development News here