You may just not realize how annoying the luck of reliability may be

To make life easier with z-wave, you should consider a high level z-wave controller, like MiCasa Vera or Homeseer Z-troller. Vera is a stand-alone hardware controller and Homeseer is a software based controller that runs on a PC, but may give you more options to interface with your Windows phones. I also would not buy all the devices right away, just get a few and see how you like it.
The keypads are great to have for scenes. For example, we have a recirculation pump, and there is a button at every sink that can turn it on for the time necessary to get the hot water to that location. The keypad though is another device that is not available from many brands, but Leviton has it. You may also get a "companion" switch if you do not need many buttons, but usually people find other things to control from the keypads. Either way, have your electrician use deep boxes with neutrals, and consider using an extra gang space for a keypad. If your fan have lights, you'll have to have it wired to use a separate switch for the light.
Z-wave locks are available from many hardware brands like Kwikset, Baldwin and Yale. For a music system I would look at Sonos. It does not work "natively" with z-wave, but has a smart-phone app and can also be controlled from a HA controller.
I would also have a cat5 wire to each thermostat location, this will allow you an option of the hard-wired thermostats. Hard-wired anything is better than wireless in both reliability and price.