I wouldn't get too hung up over looks. I suspect that the various people named Raasch all originate from the same small founding pool of immigrants and are likely to be closely related. Given that they were originally German-speaking Lutherans, it would not surprise me if the first generations married within a relatively local restricted gene pool of similar minded people.
Its no coincidence that Wisconsin features heavily in the origin of all the people named Raasch who I've checked while working on this.
I'd expect them all to look similar