Would a single currency for Africa benefit Mauritius?

No, at the moment it won't be such a good idea to have a single currency for africa. And Mauritius won't benefit from it. As such, most countries in the SADC are still developing economies and they need very different monetary and fiscal policies as compared to Mauritius.

As in the EU, there is the ECB and European Parliament who in some way govern the economic policies of the EU. However, I don't see this happening in Africa where there can be a single monetary committee or other economic council to decide on Africa's economy.

Furthermore, with Mauritius being already far in front of the other African nations, specially in the services sector, it'll be really disadvantageous for the economy to use a single currency which will not be relatively stable (what with the problems in Africa in general).

Our economy will be greatly affected if we were to adopt a common african currency. It might be easier for trading but Mauritius is the most stable country in Africa in terms of GDP and politics. Problems in other african countries will result in a decrease in the value of the common currency and that will greatly affect us.

I suppose we will try as much to oppose this law from coming into effect and there will be a lot of pressure because SADC is important to us.

1 South African rand = 3.5 Mauritian rupees
I don't think it will be a good thing to adopt this single currency for the moment.
Unless the Mauritian Rupee rises, it will be at our loss to implement this. I'm not an economist it's just my general view.
However, some part of this implementation can raise the price of our exportation.