I too have same model watch but upgraded to FAW latest firmware (highly recommend it. However you need to weigh the pros and cons. Warranty may be avoided as it might be considered you have rooted your device…
Re watch faces.
In the app where after seeing left until you reach the end there is an incomplete circle with an arrow which clears the cache. After actioning the option the downloaded faces will appear with a bin above each face. To delete, swipe the face up towards the bin. Job done!
Re battery monitoring (I assume)
When you swipe down from the watch face one of 2 screens will report battery remaining. The other screen allowed riding on/off Bluetooth network etc.
Personally, I have installed a battery app called battery widget that gives greater functionality using the watch and provides valuable information regarding battery statistics etc.
Hope this helps