Hi,
I doubt that Methodists worry about such things. However, the Catholic Church would recognize it as valid, since it recognizes the marriages of most non Catholics. But it would not recognize the marriage as sacramental because it does not recognize Mormon baptism as valid. They do not believe in the Trinity in the way that Traditional Christianity always has. For example, they do not believe that Christ is equal to the Father.
Fr. Vincent Serpa, O.P.