Well, unfortunately those effects aren't one on one compatible with 3.x otherwise they would have been implemented already. But that is what happens when you do a complete rewrite of the engine instead of expanding an existing engine.
All these features will be added eventually, priority lies with steam and linux atm.
The root node of any scene is used to attach all post processing effects. I haven't tested it yet, so I am not sure.
http://www.leadwerks.com/werkspace/blog/41/entry-1170-leadwerks-game-engine-on-steam-gets-plugin-post-effects-system/
Vegetation painting is sheduled for 3.1 btw.