I'm just now realizing, that Woundwort was saving the Redstone rabbits.
The building workers where going to build their street right through Redstone. When Marigold wasn't searching for Watership Down (because of Woundwort's takeover), they would never helped the Redstone-rabbits to escape.
Alright, the big question is: Would the Redstone rabbits got escaped without Watership Down's help? Possible.