You are correct; more languages will be announced, but so far the only confirmed ones are English, German, Polish and Russian.
Anything not too heavy and not nailed down should be movable. There should be more world interaction in D:OS than there was in DD (lighting candles, filling mugs from a keg, etc).
I'd guess there may be some standing deadwood, or something, around to burn (not just oil barrels), but I'm not sure allowing you to start a forest fire would be a great idea. Maybe you can burn trees, but if you target more than a couple you get attacked by
Smokey the Bear.
IIRC I read somewhere the world in D:OS is about the same size as DD.
