The "Override listening if my spoken command begins with" option is specifically intended to allow you to speak commands (provided they are preceded by the phrase you have set up for that option) while listening is disabled, yes.
Press F1 while VoiceAttack has focus to open VoiceAttackHelp.pdf in your default PDF viewer, which contains information on VoiceAttack's features.
If listening is enabled, or you're using the previously mentioned override option, commands from included profiles that are not overridden by a profile higher up in the hierarchy (overridden in the sense that if a command phrase exists in a profile higher up the order than the included profile, it will apply to the command in that profile, rather than that of the included profile) should be recognized, yes.