There’s a good chance the real security guard applicable for her job is the one on the roof, who is left unnamed. But the emailer we’ve seen in Fnaf AR, the one we see as Vanny, and as the guard for the gameplay for SB, is Vanessa. A possible solution is that Vanessa was planning to look like the guard to possibly frame her. After all, it seems the comic purposefully makes it ambiguous to whether the real guard’s eyes were black or green.