You are right there are plenty of things to do in Mauritius and thankfully there's many resources to find out what is available. Just take a trip to Grand Baie and browse some of the many leaflets on offer also and ask about. it wont take long for you to build a picture of what's on offer but be aware, just like many touristic areas you will be asked to go on this venture and that venture sometimes at increased rates.. Firstly i would ask the hotel you're staying at. they will have pretty much every detail and what you are expected to pay.
The weather can be a little temperamental at this time of year and the sea is not as warm as in the summer months (october-april) but it is still warm and shouldn't infringe on your activties during your stay. I have found this link for you which gives a daily forcast..
Have fun and enjoy your stay in Mauritius