Zoro already used koh or green smoke mode whatever you want to call it during the start of the fight. The reason he’s using 2 swords is likely just because he’s trying to reserve as much haki as he can
So when he builds up more haki he’ll enter koh again and finish Lucci
Hopefully jinbe isn’t the one to take out Lucci so maybe his role would be to carry an exhausted zoro back to the rest of the crew