Correct, I believe MGM used the process only once, for the finale of Good News (1930) which doesn't exist anymore unless the footage turns up some day in the Czech Republic, Australia, etc.
Regarding the two Fox Movietone Follies films, I believe they only had certain sequences in color and those were filmed using the Multicolor process that Fox used at the time.
Two other two-color Technicolor films that are extant are both from Warner Bros., Under a Texas Moon and Viennese...