I looked up the BV heating pad and it is an on/off switch, so you won't be able to lower the temperature when needed. Even with the mama heat pad you need to be able to adjust the temp, to keep the chicks happy. If it's to hot they won't want to use it.
The vertical nipples will freeze in winter, even if you heat the water. Your better option would be horizontal nipples. You can put a non floating stock tank de icer in the bucket and the horizontals will not freeze. This gives you a year round waterer.