Can You Change the Hover Name of a Rabbithole in Create A World?

No, the names are hardcoded. The only way to change them permanently is to clone the rabbitholes (doors, rugs) and to rename them in the process. The workaround is to use NRAAS Debug Enabler, this allows you to change the name for the savegame. But you would have to repeat this step every time you start a new save in your world.
Sadly, changing the name in CAW won't be ported during export of the world.