I don't really understand your first question.
The answer to your second question about reflections is that the way reflections are calculated can result in lower detail than the main render. This is done for optimization purposes. Normally water is more rough than this, so you don't see the difference. With very smooth water like you have in your image, you can see the lower detail. To fix the problem you would need to go into the "internal network" of the Renderer (press the Gear icon at the top of Renderer Node settings, then select Edit Internal Network). Then find the Render Subdiv Settings node and change the Ray Detail Multiplier to 1 instead of 0.25. This will increase render time. If you don't see the Render Subdiv Settings node, try pressing the Animation Check button on the Sequence/Output tab of the renderer, then look again in the Internal Network.
- Oshyan