LC is only calculated on the local machine - vray does not use DR for LC. For the irrmap - if you are using "incremental add to map" and using a frame rate 1/6th the speed of your final render, the calculation goes pretty quick, so shouldn't be too much of an issue to not use DR. Once you have the GI solution, then you can use your DR for the final renders. (make sure the saved maps are available for all your network.)

The last render you post are quite good... It is missing some grass at the base of the container, a background, some soft shadow on the ground and a more realistic sky. But light and shade, and exposure of the structure are quite good in my point of view. Wait and see the progress of this project of yours.

SO i made a lil video containing some "special" vray settings... the most difficult part were the batch render + dr somehow i managed to make the 3 pcs run their cores to 100%, then i did something and they work 100% then 0 and so on... heres the video http://www.youtube.com/watch?v=a3K9dv4OyPo ill post some pics later on... ill take any advice involving vray settings...