No, it is not possible to know whether a sent message has been received by the recipient. The user manuals only describe the sending of SMS messages without mentioning read or delivery confirmation functions.
No, unfortunately the BT profile isn't complete: it can just connect to a headset - headphones/microphone.
If you can make a dev for Android SmartWatch, detecting the loss of BT signal doesn't seem impossible, but it does require solid skills in the field.