First of all I guess we should be realistic knowing that it's impossible to have a 3 weeks weather forecast. Even here in England we get the 3 days weather all wrong most of the time. Not only Summer is prone to Cyclones, Winter weather can be affected by anticyclones but they are not as fierce as their cousins but sometimes they can bring winds and heavy rain that might hinder air traffic.
The security of tourists remains one of the priorities of the Hotel and Air Mauritius I believe and I'm confident that they will judge it right if the weather is too bad to fly. You don't have to worry.
Expect a couple of days of rainfall as worst case scenario and take it easy...the weather should be fine.
Enjoy your holidays