1- No. That's the short anwser, but, the thing is if you use standard materials, most properties will go thru to octane, such as diffuse, bump and some others and any map associated to those properties. But since I work with octane I've changed my workflow with max. If the material doesn't have any map, I just assign a standard "out of the box" material, most of the times usually grey, if it has any map, I assign only one channel (say diffuse) , then I adjust the uvmap in max. The reason is that in octane is much much more intuitive and easier to tweak materials since you have real time feedback on how it really looks in your scene, so wasting time in max assigning anything else is useless. Lights in octane are mesh emmitters, so just assign a material to the mesh you want to use as light in max (a plane, a box, a sphere, whatever you can think of...) and in octane use a diffuse with blackbody emmitter and add IES and all that fancy stuff
2.- Yes and No, the inbuilt max obj exporter doesn't export particles per se, so you have to convert them to mesh, use mesher or anyother method you like. This might change once more mesh export file types are supported by octane besides obj files.
3.- yeap
4.- displacement I think is planned, althou don't know when.
