New set up guidance required

Hey guys, I played with home assistant a couple of years ago on a RPi, a couple chrome casts, a smart tv and WiFi presence detection.

I’m redoing my hallway and downstairs toilet and getting the ceiling re skimmed so was thinking now is the time to knock the walls and celing about a bit. I started by thinking of a PIR controlling a White LED strip for some trough lighting. Then it spiraled from there, so this is where I’m at.

I’m thinking of Z-Wave for lighting and power:
Fibaro RGBW, or Qubino RGBW Dimmer Plus can be configured to control the hall way and toilet light strips, which would give me two spare outputs, so I’ll probably convert the porch light to 12V. Ideally I’d also like to control the extractor fan, so will probably need a 12v relay to switch the 230v
Then I could use 3 of the 4 inputs for the PIR’s (toilet, hall, and porch)

The next thing I’m thinking about is door open / closed and locked detection. The z-wave modules for these are a little pricey, an I’d want something I could hide in the door frame. I could wire up some reed switches to an RGBW module, but I wouldnt be using the outputs. Too me that would seem like a waste, only using half the module, again, the cost is adding up a bit. I don’t care so much that it Z-Wave, are there any alternatives? Something like an input module that I could link to my system over serial or usb? I could use an arduino, but I’m a bit concerned that I’d have no come back from the insurance if I burnt the house down!

Any suggestions?