Joe,
Each light that you want to individually control, will need a separate high voltage relay (Aux relay) and separate step a down transformer.. Within reason, if you want all the lights doing the same thing, and being the same color, at the same time, then you can use one relay and one transformer...
You are not supposed to mix low voltage circuits, in the high voltage section of the load center..
This is the type of stuff that should be decided long before it is time to wire up the automation... ☹
And NO, you can't use the internal system 12 volts to drive external lights..
Thanks,
Jim R.