The Alexa routine looks fine.
The next step is to ask in the author thread for the VEdge Creator. It may be that you need to use a different virtual device profile: some work more reliably with Alexa routines than others. But someone there will be able to help you.
[ST Edge] vEdge Creator: a virtual device generator for end users
Also, I know this is a lot of work to set up something which seems like it should be so simple. 
. In this particular case it is a combination of incompatibility between the two platforms since SmartThings doesn’t see the outlet and at the time of this writing Alexa won’t trigger off a leak sensor. I’m sure you’ll be able to make it work eventually using a virtual device, but I know it must feel frustrating right now.
The alternative, of course, is to use a different smart plug that SmartThings can see. Then you wouldn’t need virtual devices and could just use a SmartThings routine. But of course that would cost more money. 