What kind of Southeastern Asian River plants would you recomend?
I dunno. I would have to do some research if I was going to have this tank. I grow mostly Amazonian fish and right now am using any plant that will do well in my tanks. At some point I'm going to go all Amazon with the plants too, when I can afford to be choosey.
Yes, smooth rocks make sense and are natural to this tank but rough rocks help with bacteria colonies and holding bits of food for fish and your shrimp to pick at. I'd at least keep one rough rock if it was my tank.