Has anybody played for both the Kansas City Athletics and Kansas City Royals baseball teams?

Answer 1

No one. However, Bob Ferrick, Sr. played with the Philadelphia Athletics, coached with the Kansas City Athletics and was the Farm Director of the Oakland Athletics. The only other person affiliated with the team in all 3 cities was Lew Krause, Sr. who pitched with the Philadelphia Athletics and was a scout for both the Kansas City and Oakland Athletics.

Ironically, Bob Ferrick, Jr was a columnist for the Philadelphia Inquirer and Lew Krause, Jr. was a suburban Philadelphia schoolboy bonus baby pitcher. They both grew up in the Philadelphia area based on their Dads affiliation with the A's. Krause, Jr also pitched for the KC and Oakland Athletics. He signed with the A's because his Dad was their scout. It was reported that Charlie Finley hired Lew Sr in an effort to sign his son.

Answer 2

Pitcher Ken Sanders played with the Athletics in 1964 and 1966 and pitched three games for the Royals in 1976. Pitcher Aurelio Monteagudo pitched for the Athletics between 1963-1966 and pitched for the Royals in 1970. Pitcher Moe Drabowski pitched with the Athletics between 1962-1965 and pitched for the Royals 1969-1970. Pitcher Dave Wickersham pitched with the Athletics between 1960-1963 and pitched for the Royals in 1969.
There may be others but these four were all I could find using the Athletics roster from 1965-1967 and the Royals roster from 1969-1971.