If you are talking about FECN (forward explicit congestion notification)then that won't help too much. It would only slow down the traffic after you've already lost packets. You'd be better off doing CB Shaping on your end with priority for the voice. You may be able to use auto qos voip command if you are not familiar with MQC QoS.
No, I don't think has to do with channel groups. It appear FEC for 3G has been standardized only recently, and may require licensing from the developers, so probably a question appropriate for a Cisco PM.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...