1. Well as much as I would like to have an officially implemented third person...there isn't. There's lots of scripts out there that allow for third person but none are perfect. It is possible but it depends on your level of need.
2. This is the same for FPSC with the exception of rag-doll. You can have enemies die and rag-doll in whatever position they fall. this all depends on the environment and objects they fall on to.
3. This is purely a model/texture standpoint in any engine. You can have the same model and right click him, then change the texture in it's properties. In this way you can have a multitude of types. More major changes require separate models. As I said this is in any engine; not specific to FPSC.
Hope that helped.
Model pack 66-99 high quality items...cheap!!
"Who loves ya baby!"