ATC is there for you and not the other way around. IF they want me to slow down and descent at a high V/S then I'll tell them that they've got a choice, either speed or v/s/altitude. Sometimes it's daft using speedbrakes for what ATC is trying to achieve and it's just wasting too much 'free' energy.
On the Embraer V/S is not used. We use Flight Path Angle instead. But yes, you can use speedbrakes in both modes.
In v/s you are not speed protected so we tend to use Flight Level Change or FPA. In FPA you are also not speed protected. but it maintains a given descent angle irrespective of config/speed/wind etc.