Just looking at the logistics of a Savannah buff hunt departing Brisbane for Cotonou - is there really any other options than getting oneself to Paris Charles De Gaulle and popping down on a Air France flight?

Any horror stories to be mindful of if flying to Paris on a different airline with firearms and swapping carriers at CDG?

Yes you can use air brussels.
Avoid air Maroc who also fly there I think.

Air France is fine with rifles. Never had any issues.

I am flying to ougadoug with air Maroc... anything I should know?

I just discovered SAA fly to Cotonou (with a fuel stop in Libreville) on what looks to be a 3 days a week service.

Is this service reliable or likely to eat into hunting days in big chunks due to delays, rescheduling or just not running when you want them to?

SAA does seem to offer the most weight of checked luggage but from past experience there's no guarantee it'll arrive on the same flight