Both Bluetooth and Wifi not working on Galaxy S3 Mini
I had the same problem. WiFi and Bluetooth modules use the same antenna. This is a hardware problem and I fixed replacing the antenna but you should the check other possibilities. Check this link out: http://blog.brokenlcds.com/samsung-galaxy-note-2-bluetooth-and-wi-fi-problem/

About your second issue, it also sounds related to the antenna of the communication module.