I guess you are talking about skeletal animation like Half-Life uses it (just to name one)? I'm not too sure that this will make its way into jPCT in the near future...I know that it would be a nice to have feature though. Please don't count on it...but then again, i once said the same about OpenGL and MD2 support..
I know that this isn't a very satisfying answer, but it's all i can say about this topic ATM.
I don't quite understand the second question...why do you want to call LWJGL directly?
To explain how jPCT makes use of LWJGL: The one and only class that knows something about LWJGL is the GLRenderer (as an implementation of the IRenderer-interface). No other class know a single bit about LWJGL (or any other renderer implementation).