By using that CM installer to unlock bootloadder and install cwm and cyanogenmod, is there any change to brick the device or any incompatiblities ?? Just take the phone out of box install that CM app on the phone and on the pc and start ??
Edit: The app is no more in playstore, from where can i take that official app ??
It is a Nexus device, so it is hard to brick it.
I have been using custom ROMS from first day I bought the device and I haven't got a problem. As I said you can revert back to stock ROM or just try another ROM.
No one can warrant you that everything will work and there is always a chance of brick, but not too much if you do everything right.