Most likely the original Norwegian certificates, both for Pax, cars and trading limitations, have been changed, or ignored. Probably a lot more Pax and few if any cars carried.
The cargo would have been anything and everything that is traded between West African ports/countries, incl. live animals and fresh produce in wicker baskets. All in sizes that can be carried on board by hand or on the head of females.
How many Pax and how much cargo was carried on this trip is hard to say, but having observed ferries operating in Nigeria (incl. from Calabar) and other places in Africa the limitation is set by what is available, not by any consideration to load line, stability or other mundane considerations.
The bow and stern configuration was originally suited for standard Norwegian ferry wharfs, with ramps on shore, not on the ferry:
The hydraulic lifting system is remotely operated from the ferry. Ticketing is done by the ferry crew on the crossing, or electronically on boarding. There are no shore attendance on the wharf.
Here is a typical call by a shuttle ferry trading across the fjord from Stranda to Liabygda in Sunnmøre:
From the picture of her in Cameroon it looks like she MAY have got a ramp fitted on Port side to drive vehicles on/off when needed. The bow visor would most likely be welded shut, or at least not operational.