Re: Bluetooth keyboard
It is certainly possible that the jailbreak is generating some sort of interference if that is the only system change you have made since you started experiencing issues. Disassociate your keyboard and iPad and fully power down each device. Leave the iPad off for around 10 seconds and reboot it. Once it reboots, reconnect your BT keyboard.
Two major possibilities are interference with the BT signal and some piece of software causing the BT controller to act strangely on the iPad. This is a hazard of jailbreaking though to be honest I've never heard of PanGu causing BT to breakdown. If its interference, you'll have to move it away from the source of interference. Usually this isn't a huge issue with BT because the devices are close together but if you have a lot of different gear shooting out radio waves in a tight area, that could do it.
If you keep having issues, I recommend installing and using BluSelect. It's a pretty amazing bluetooth controller for jailbroken iOS and it is possible that it will eliminate the issues you are having with the stock bluetooth controls.