To clarify, while you are correct about the Z-Wave devices being a mesh network, there wouldn’t be Z-Wave devices wired to the DSC panel.
Z-Wave devices compatible with Alarm.com (and the Go!Control panel) would be devices such as lights, locks, thermostats, etc.
It sounds like you are using a 2GIG TAKE-345 module to convert existing wired sensors (Door/window contact, motion, etc.) into wireless, correct? The TAKE-345 converts the wired sensors into wireless, communicating sensor status across the 345MHz protocol to the Go!Control panel.
Wired sensors like Door Window contacts are not wired for power but to communicate status to the DSC panel, but devices like wired Motions and Glass Break sensors are wired for power and communication.