Is a WiFi enabled Smoke Detector Alarm Sensor & H20 Leak Detector combo possibl

First time posting here, and Im somewhat new to the arduino world. I have done very little experimenting in my limited time with the platform (I have been in the process of moving for going on 10 months now, long story) anywho I am now in my own house and would like to add some automation, the first step being two water leak detectors, a smoke alarm sound detector, and a garage door opener, all running from two arduinos on various floors and wifi enabled. Here is my ideal setup:

Arduino 1 (Garage)
Primary task:

  • Detect water leaks from washing machine (located in room off of garage)/Send these alerts to Email, SMS etc.
  • Use as wifi garage door opener
    Secondary task:
  • Motion detector
    Arduino 2 (Basement)
    Primary task:
  • Detect leaks from water heater and sump pit/Send these alerts to Email, SMS etc.
    Secondary task:
  • Detect fire alarms both in basement and upstairs (via sensor placed upstairs, but wired to/Send these alerts to Email, SMS etc.basement arduino)

Im not sure if all of that is even possible with two arduinos, and what other add on items/shields I would need. I would assume a wifi shield or ESP8266 for the Wifi connection as well as some type of mic setup to detect the fire alarm, and sensors to detect water leakage. I skimmed over a how to on the garage door opener and I think I have a relay shield somewhere in all my stuff. I would like to get a good list of major components required (IE: shields, detectors etc) and sources for them if possible, I am not to concerned with resistors, caps, etc, as I have a bunch on hand, unless they are super specific (like cant run down to the Shack and pick them up). Id like to be running all this on the two Arduino Uno's I already have if possible, if not I am willing to get more to make it happen. Thank in advance. I researched this a little but thought the specific questions warranted a new thread.

All seems very do-able to me. You will (obviously) have to have some sensors for fire and water- which ones you choose will determine the direction you go in. For example you need to decide if the water sensor has to detect a single damp spot (like the sensors in the sub-floors of computer datacenters) or only go off if a decent pool of water forms.

You will also need some kind of Wifi device, either a shield (easy but more expensive) or the (cheap but more difficult) ESP8266 series. Main issues with ESP8266 are 1) you probably need to reflash the firmware and 2) its a 3V3 device so needs level conversion to work with standard arduino.

As a start point I suggest you build something on your bench that will send an email and SMS via WiFi when you press a button. That will get you most of the way there while you decide on sensors.