I have the following issues after update. First my ringer keeps silencing after I miss or decline a call. Second whenever I restart my phone it reverts my keyboard back to the Samsung one instead of SwiftKey
I was actually able to remove the Samsung keyboard completely, however that method requires root access and a tool called No Bloatware (available on Play Store). The Samsung keyboard app is located in Settings > Application manager > slide to the left until you see the ALL tab. Scroll down and you'll find the Samsung keyboard app, but the Clear defaults box is greyed out preventing you from setting the Swiftkey keyboard as the default keyboard.
I've never encountered an issue with the ringer volume on the S2x, but I do have the paid version of Volume Ace installed, there is also a free version. You could install a Volume Ace widget on your home screen where it will give you a way to instantly access the ringer, notification, media, alarm, voicecall or system volume settings.