Option 9: The wackware-bell with MIMOlite. It’s been perfect for me for six months or so with instant notifications. I already have a cam on the porch area. Also works well with a Homeboy if your porch is protected from the elements.
Note, will cause MIMOlite “device failed to update mesh info” message during Z-wave network repairs since the device only powers up for a second when someone rings the doorbell. So that slows down your Z-wave network repairs by a few minutes. No big deal though.