[haus]

From what I've read, 1c is not an option with the stock voice dialer. There's nothing in the 2.3 changelog that indicates support for voice dialing confirmation, but folks with a Nexus S might be able to shed more light.

As for #3, OP didn't specify clearly whether this was for checking headset battery life and listening to A2DP music through the headset, versus *controlling* music on the phone and checking *phone* battery life via the headset. The former options depend on the headset as benc indicated. The latter options depend on the phone. With Windows Mobile voice command, you can un-check the options for voice command to listen for prompts about playing music and speaking phone status (I don't think this saves any memory usage, but it might result in fewer mistakes in understanding commands since there is less to "listen for").

1c (voice dial confirmation) is important to me too. I could see a scenario where I try to dial someone named Michael and the phone starts playing Metallica. Having confirmation (and the ability to turn off media commands) would be good things.