[The Might]

I think this idea is quite plausible, especially since the name also is a reference to the first age. As Sauron was after all the Lord of the Werewolves, it makes sense that he would have used this as inspiration for Grond.
And since Grond as a name remembered of one of the greatest weapons ever made, why wouldn't the shape remember of the greatest wolf to ever exist.
The linguistic part only supports this.
All in all, it makes to me more sense that it was Carcharoth/Draugluin or Sauron himself in wolf shape rather then some regular wolf.