wind against tide they can kick up, and as you would expect more wind the bumpier the ride. Easy enough to avoid by stuffing a few degrees of helm on as you transit past Beachy or Rye
Mild to tolerable. From memory, there is at least 4m over them, so they do not present any real threat to yachts in winds up to F6, but there can be quite a tide rip over the Horse of Willingdon on spring tides which makes for a little bit of excitement. The biggest risk is of running into one of the many fishing boats out there.
Other minor local dangers are close inshore: Head Ledge, for yachts tide-dodging off Beachy Head, and Coxheath shoal.