Kinda 2-in-one headcanons, but I like the idea of Michael having a different mom than C.C and Elizabeth. Michael's mom has the surname of Schmidt for a couple of reasons.
One is Fnaf 1's nightguard name. Mike (Schmidt) is a shortened version of Michael, and it's the only fake name close to his real name. So her very well could be using his mother's maiden name.
Second, although im not sure how true this all is since I looked it up, but Schmidt is a German surname.
Germans are slightly more likely to have blue eyes than any other eye color. And while not the most common hair color, a high percentage of Germans have brown hair.
In Sister Location, where Michael is walking down the street, he starts off with brown hair and blue eyes. This only changes when he decays.
So Michael could be part British, part German. He could just have a British accent because he grew up with William.
(Not sure how to word this, but if I'm wrong on anything from paragraph 3 or down, please let me know! Same applies if you're German or British and this offends you.
This is just a headcanon that I thought of and like. I'm not British or German myself, so I very well could be wrong.
The only reason I believe Schmidt to be a German surname is because I looked it up on the surname version of behindthename.)
