but you know..if by upside down catfish, you specifically mean synodontis nigriventris, that would be a good choice for a SA tank
and multipunctatus would be an okay choice for an mbuna tank. the thing is - the cat comes from lake tanganyika, and the mbunas come from malawi, and that makes a big difference for the fish species and water chemistry.
synos that live in malawi:
Synodontis njassae
other than that, the multi i think may be the best choice