Mimionmnixon -
That DVR/NVR will run 16 channels simultaneously.
You will be able to record and stream video to remote clients at the full frame rates =
At 1080p (2Megapixel) you can run all channels at 15 FPS (frames per second)
At 720p (1 Megapixel) you can run all 16 channels at 30 FPS
At 960H / D1 / or lower resolution - you can run all channels at 30 FPS
You can mix speeds also - 1 cam at 10FPS, another at 30FPS - they are individual settings.
On your existing cameras, you will not see much difference in quality.
With the unit you can add HD-CVI cameras at 1 or 2 megapixel and then you will see a huge difference.
Or you can add 2 IP cameras and you will see a huge difference. (IP cams will go to channels 15 and 16)
As long as your existing cables are good quality, you can use them for HD-CVI cameras.
The bit rate is a little different setting - this is the amount of data used to 'fill in' an image.
The 2 megapixel HD-CVI cams will use a bit rate of 2048Kbps or less. (They don't need to be that high)
In most cases with analog cameras and HD-CVI cameras you won't need to worry about the bit rate - that comes into play more with IP cameras at higher resolutions (3Megapixel and up)
To sum up - the answer to all of your speed and streaming questions is 'Yes' it will do that easily.
Let me know if that helps.