None of it will require custom program, @ady624 created a powerful new SmartApp called CoRE and it will allow you to do everything that you mentioned.
My DTH for the GoControl Siren does have a chiming/beep feature, but the device’s response time isn’t reliable so sometimes it does a quick beep like it’s supposed to and other times the siren turns on for 2-3 seconds.
The GoControl door/window sensors work great for turning on and off lights as you enter/exit rooms, but the GoControl motion sensors can be a little bit slow to react. They still work, but it may take a few seconds for the light to turn on. Also be aware that once they detect motion, they won’t report no motion until there’s been at least 1 minute without activity. Default is 3 minutes, but the DTH allows you to change it.
I originally tried using the geolocation feature, but I found that if I closed out of the SmartApp it wouldn’t detect that I’ve left or arrived and even when it was open it didn’t always work right.
I ended up getting the Arrival Sensor which costs about $30 and I haven’t had any problems with it. If you get this, be aware that the battery level will rapidly drop for the first few weeks, but my battery has been bouncing between 30% and 50% for several months so it’s not as bad as it seems.
WAF is always a concern, but if you don’t try to automate everything at once, don’t eliminate the manual way of doing things, and show her how to manually turn off the siren if it ever gets stuck on, she should be fine.