using servos which have the ability to lift 14kg's,
If you by 14kg means they have a torque of 14kgf-cm, they're pretty large - do you have them already?
I have sourced a recargable 9v battery will this be powerful enough to operate each servo and run a brushless motor?
If you mean a PP3 battery (rectangular battery/transistor battery/whatever you call them), you won't even be able to feed one of the servos.
could I add in a second power source easily?
Since I don't know what you're building or your skill level, I can't say how easy you'll find it, but motor and servos runs fine on a "secondary" battery, as long as you keep the ground connected to the existing ground (and the servo signal coming from a micro-controller or similar should not be connected to this battery at all).
Which specific servos and motor (Link)?