Odds are courtesy of SportsBetting and can be found here: 

Will there be a World Series?
Yes -450
No +275

First manager fired during 2020 regular season
Scott Servais +800
Brandon Hyde +900
Dave Roberts +900
Rick Renteria +900
Bud Black +1000
Derek Shelton +1200
Ron Roenicke +1200
Don Mattingly +1400
Ron Gardenhire +1400
Dave Martinez +2500
Luis Rojas +2500
Brian Snitker +2800
Charlie Montoyo +2800
Chris Woodward +3000
Mike Matheny +3000
Craig Counsell +3300
David Bell +3300
David Ross +3300
Mike Shildt +3300
Torey Lovullo +3300
Aaron Boone +4000
Bob Melvin +4000
Gabe Kapler +4000
Joe Girardi +4000
Joe Maddon +4000
Rocco Baldelli +4000
Dusty Baker +5000
Jayce Tingler +5000
Kevin Cash +5000
Terry Francona +5000

Will an MLB manager be fired in 2020?
Yes -1500
No +600

Total MLB managers to be fired in 2020
Over 2.5
Under 2.5

How many games before first manager fired
Over 18.5
Under 18.5