No, you can't use USB bluetooth dongle (I tried, went through 3 pieces, all the 'unknown device is connected').
TV already have bluetooth module, but webos doesn't want to see not LG devices, only 'lg tone' bluetooth headset and lg bluetooth soundbar. I'm sure - it's only software limit, perhaps especially...
I think, if you write about 'bluetooth support' in tv device - you MUST support A2DP, otherwise what's the point in bluetooth in TV???
+1 for A2DP in WebOS WishList - I think it is the most desired feature that can be very easy to implement! (i am programmer)
