The below pictures show three lovely women getting ready for a scene. They are all dressed identically, with same hairstyles and outfits that would be out of character for Michaela (Megan Fox) to wear. Blue jeans, a shirt and a plain leather jacket would fit that character more.
From the call sheets, the three Can-Am Spyders (commenters think Arcee may be 2 Trikes instead which were also on the call sheet) are referred to as Arcee Motorcycles and in scene descriptions the plural ("bikes") is used. There are also two of the Arcee drivers specfically identified, Jessie Graff (Arcee Rider #1)and Melissa Hartman (Arcee Rider #2). From a quick Google search, Jessie Graff is an experienced stunt woman who has worked on Die Hard 4, The Dark Knight, and GI Joe. I think Melissa Hartman is the married name of Melissa Stubbs who has done stunts on Indiana Jones 4, Battlestar Galactica, and Bionic Woman. I guess the third woman was picked from the casting call that occured last month.
Considering the precedent of hologram drivers from the first movie, it makes sense that Arcee would use three hologram drivers when she is in vehicle mode. Three bikes and three drivers, strikes me as more validation that that Arcee's vehicle mode is three Can-Am Spyders.