I did some loop-ups concerning your request and found that the Muller-Schmidt family originated from Germany, so you have to concentrate you on that region. If you are interested I could mail you some records I found and give some explanation to them but I need an e-mail address to mail them. You can eventually send me a private message with an e-mail address.
1) the signatures of Müller Catherine and Jules Vandermeulen
2) names Jacob Müller and Maria Schmidt taken from a German record