Regarding 1): 
If you don't want to descend into a Behaviour's context menu to choose 
"Activate Behaviour", you can select the respective option in the 
Extended Options at Prefs > Menu > Menu size & effects. The activation 
of a Behaviour will also start the app it controls if it's not already 
running. If you want to explicitly bring an already running app to 
front (and make it the focused application), you can choose "Bring to 
Front" from the respective Behaviour's Context Menu.

Regarding 2): 
Remote Buddy already can do that. You can either use

Menu Root Level > System > Application Manager > .. > Force quit

or

Behaviour Context Menu > Force quit

Regarding 3) 
This functionality is already there. You can map the activation of a 
Behaviour (and thus trigger the launch of the app controlled by that 
Behaviour, if it's not already running) by selecting the respective 
action found under "Behaviours > Active .. Behaviour" from the popup 
in the respective mapping table at Prefs > Mapping.

Best regards, 
Felix Schwarz