I have isolated a method for making things work, for others who may have similar problems:
1) Connect headset by turning it on.
2) Set headset to headset (not a2dp) mode using blueman-manager
3) Disconnect headset from blueman-manager
4) Reconnect headset from blueman-manager; it will show Audio Profile: off
5) Set audio profile to A2DP
At this point, it generally seems to work. Shorter sequences have not yet reliably worked for me. Some parts of the dance can be done in pavucontrol, but it's easiest to do it all in one place.
I have isolated a method for making things work, for others who may have similar problems:
1) Connect headset by turning it on.
2) Set headset to headset (not a2dp) mode using blueman-manager
3) Disconnect headset from blueman-manager
4) Reconnect headset from blueman-manager; it will show Audio Profile: off
5) Set audio profile to A2DP
At this point, it generally seems to work. Shorter sequences have not yet reliably worked for me. Some parts of the dance can be done in pavucontrol, but it's easiest to do it all in one place.