About Number Three: What do mean by that? ("straightforward bounds checking")
As in, set the influencing bounds for the light.
About Number Four: In Xith you can have different Texture-Unit-States,like in Java3D, where you can also blend around with alpha-textures. + I believe there is also a other way of doing this (there has to be a bumpmapping demo somewhere around, that uses that), but you'll have to have the GL-Extensions for that.
Really? I never seemed to be able to do proper alpha-compositing with TextureUnitStates in java. But I guess that would be another topic. Thanks for the info.