I've heard of a couple coach that have there bodybuilders stop doing stair or high resistance bike for cardio a month out and just use the tread mill to "preserve" muscle.
Then I've heard of people doing less actual cardio and more things like lunges for HIIT cardio.
As for calves (aside from being highly genetic)
I think that taxing them with very slow reps , and deep stretch and long contractions has worked for several people I know.
3 second stretch at the bottom on an elevated block , a 3 second ride to the top , 3 second squeeze then a 3 second negative , use a weight you cal only do 12-15 reps till failure.
We rarely put this kinda stress on the calves.