Unless there’s any problem with LWJGL 3, the only reason I can think of to use LWJGL 2 would be that it has a lot more resources available for it… but that may not be such an issue really.
So should I use LWJGL 2 or 3 for my new game?
You should probably just switch to LWJGL3, I am pretty sure there not maintaining LWJGL2 anymore, so any bugs in LWJGL2 are more like features now.
The biggest change in LWJGL3 is GLFW, which has sample code on their website to create a display.
The OpenGL is still OpenGL, your best bet for OpenGL tutorials is going to be C++ code tutorials, if a method does not exist from the C++ article, a quick check of the javadocs and the method name will show you the method and its paramaters.