Were there any starting pitchers in MLB history to go undefeated in a single season like 34-0 or 35-0?

Answer 1

No.

The most wins an MLB pitcher had in an undefeated season is 12 by Tom Zachary of the 1929 New York Yankees. 9 of his 12 wins came as a starter.

Several starters have been close ...

1) Johnny Allen went 15-1 for the 1937 Cleveland Indians. He pitched in 24 games and started 20 of those 24.

2) Greg Maddux went 19-2 for the 1995 Atlanta Braves. He pitched in 28 games and all were starts.

3) Randy Johnson went 18-2 for the 1995 Seattle Mariners. He pitched in 30 games and all were starts.

4) Freddie Fitzsimmons went 16-2 for the 1940 Brooklyn Dodgers. He pitched in 20 games and started 18 of those 20.

5) Tom Seaver went 14-2 for the 1981 Cincinnati Reds. He pitched in 23 games and all were starts.

6) Ron Guidry went 25-3 for the 1978 New York Yankees. He pitched in 35 games and all were starts.

7) Cliff Lee went 22-3 for the 2008 Cleveland Indians. He pitched in 31 games and all were starts.

8) Preacher Roe went 22-3 for the 1951 Brooklyn Dodgers. He pitched in 34 games and started 33 of those 34.

9) David Cone went 20-3 for the 1988 New York Mets. He pitched in 35 games and 28 of those 35 were starts.

10) Orel Hershiser went 19-3 for the 1985 Los Angeles Dodgers. He pitched in 36 games and 34 were starts.