FF can be changed without problems, smaller notes will sometimes be refused. Often you can also pay with FF immediately, but not for small amounts. Credit cards Not useful in Mali. I don't have much info on flights within the country. A pinasse is a big motorized pirogue used to transport cargo.
Passengers simply live on the cargo.
We had 30 passengers on our boat. It's not very comfortable of course sitting and lying on the cargo, and there's no toilet. It's best to have a sleeping mattress. However, the boat stops regularly to load or unload cargo. Rice is extra at 2.000 CFA for the whole trip.