Rulings

Maha’s last ability overwrites all previous effects that set those creatures’ base toughness to specific values. Any toughness-setting effects that start to apply afterward will overwrite this effect.
Effects that modify a creature’s power and/or toughness, such as the effect of Overprotect, will apply to the creature no matter when they started to take effect. The same is true for counters that change its power and/or toughness and effects that switch its power and toughness.