I can't answer your question with facts, but I'd guess yes they'd help. I can't see how farmer's walks would hinder your deadlift. They're a great functional exercise that will help build up your forearms and work a lot of stabilizing muscles in your body.
Lots of tension over time there. I'd also suggest that they will help protect you from injury vs only doing "maximum strength" exercises.
No, they are not an explosive exercise, but I still think they will benefit your deadlift and overall strength. They're also often a staple in strong man competitions - and I've never seen wrist curls and skipping rope on there.