You can do that if you have something like traefik reverse proxying to multiple containers. It’s lots simpler to have two droplets, one of which you could delete when you’re not using it. That way, you’ve still got a Standard Install that’s easy to debug as well as get help here.
EDIT: And if you want a configuration that includes Traefik as the front end with multiple Discourse, WordPress and Ghost containers as well as prometheus and Graphana containers to make pretty graphs I can do that for you.
My preferred way to do that is by keeping backups in an S3 bucket (or GCP or Digital Ocean equivalent). You could have two containers share a backup mount if they’re on the same server, but the S3 solution is really nice and makes it easy to move to a new server should disaster strike.