Regarding Bluetooth, it might be doable, but it would involve a lot of work as right now we just passthrough the USB packets from the modem to the PC - we would need to act as a target for the modem, set up the IP stack in the OS and then pass it via Bluetooth. Please also consider the limited data rate of BT tethering - it could be unacceptable with some hard data usage sites.
On the other hand, syncing with Mudita Center via Bluetooth should be much easier to do. I’ll pass the idea further 