No one has created an Edge Driver for a cloud to cloud device: by definition, edge drivers run on the hub, so are not cloud to cloud.
Instead, what you are seeing is that in some cases (it depends on the device) it is possible for the hub to communicate directly over local WiFi to a device whose official integration is cloud to cloud. At that point it is no longer a cloud to cloud integration because it is not going through the manufacturer’s cloud at all.
One of the oldest examples of this was a Philips hue bridge. There have been two official integrations for years: one that was cloud to cloud, and one that was using the local LAN. If you didn’t have a smartthings/Aeotec hub, you had to use the cloud to cloud integration. But if you did, you had a choice of two different integrations. One that was cloud to cloud, and one that was local. That will continue to be true after the groovy cloud is shut down.
Now it is also possible to connect in one of two different ways for some devices: one which is cloud to cloud through the manufacturer’s cloud, and one that is local using an edge driver.
Being able to do this requires that the manufacturer have published an API so you know what messages to send locally. Not all manufacturers do.
So what you were mostly seeing is community developers who have identified API options for a local LAN connection to a device that also offers a cloud to cloud path.
If the current cloud to cloud integration is official, and it is identified as a “placeholder“ in the IDE, it should continue to work in exactly the same way, no matter what happens with edge drivers. You won’t have to do anything with them, and they won’t have to be transitioned, they already work.
If the current cloud to cloud integration is unofficial, and was created by a community member, like the old MyQ integration, it won’t be automatically transitioned, and it will stop working when the groovy cloud is shut down. So you need to check in that author’s thread to see what alternatives they are suggesting. It might be an edge driver, but it also might be a new and different cloud to cloud integration, probably one using the new REST API.
IFTTT is working on a new version of their integration, which will not require the groovy cloud: I don’t know if it’s completed yet or not.
SharpTools has completed their new version, which is cloud to cloud but uses the new REST API, not the old groovy cloud. If you run into any issues, ask in their forum.
Philips Hue, Arlo, Ring, SmartLife, the official Ecobee integration, the official cloud to cloud TPLink Kasa integration, Alexa, and Google Home should all continue to work as they work today, and will not require edge drivers.
I don’t know about the other ones you have listed.