Hey there kathy Corby,
Thank you for using Apple Support Communities. Congratulations on getting your Apple Watch Series 5. I understand you’d like to verify if fall detection and the International emergency calling feature will work if you don’t have an active cellular plan. I'll be happy to help with this.
In the Use Emergency SOS on your Apple Watch article it states:
"International emergency calling
Apple Watch Series 5 (GPS + Cellular) can call local emergency services when you're in another country or region. When you start an Emergency SOS call while abroad, your watch connects to local emergency services, but it doesn't send your location or a text message to your emergency contacts. In some countries and regions, international emergency calling works even if you haven't set up cellular service on the watch. Learn which countries and regions are supported.
Just like when you use Emergency SOS in your home country or region, your iPhone needs to be nearby if your Apple Watch Series 5 isn't a cellular model."
You can read more about the fall detection feature of Apple Watch here: Use fall detection with Apple Watch
Cheers