Re: Battery life.
Looks like a lot of background activity going on with your apps. Also, it would be helpful if you tapped anywhere on the apps list in the screenshot you provided so that it can give us a rundown on specifically how long each app was running in the foreground and background. Judging by the Usage time I say that's average so you should be able to get through with about 8hrs of actual usage, if this is a regular 6S then it's quite good, if this is a 6S Plus then it's very average or maybe a bit subpar. Try these below:
I recommend turning OFF Background App Refresh found in Settings>General>Background App Refresh. Turn Location Services OFF unless you need it so that your phone and any other apps running in the background don't track your every move and thus use more battery. If you have email setup on your phone, make sure emails are set to Manual and not Fetch or Push, set them to retrieve emails Manually. Also, you might want to try quitting all your apps and do a hard reboot (home button + sleep/power button until the phone shuts down) and charge it to full, could be something stuck in the background like a bad process or some junk that needs to be purged from the memory. Once that's done, just use it like you normally would and see if that changes anything. If not, try a fresh restore of your phone (restore as NEW and not from a backup). If that changes nothing then might be a faulty battery in which case take it to the Apple Store for a diagnosis and you might get the phone replaced for a new one. Hope this helps.
One more thing, make sure you've also turned off Automatic Downloads for Music, Apps, Books and Updates, found in Settings>iTunes & App Store. Turn those all OFF. Should make a difference.