So, that may not be the right question. The Malachi/Caboclo trade had no bearing whatsoever on the George Hill trade. However, the George Hill trade required us to have an empty roster spot, as we received both Johnson and Shumpert while only sending away Hill. You have to have roster space available for every player you trade for - you can't trade for a 16th player and immediately cut them to get to 15, you have to be at 15 max including the players you receive from the trade. As a result, we cut PapaG to get down to 14, then traded Hill for Johnson/Shumpert to end at 15 after the trade. Then, we subsequently bought out Johnson and got down to 14 as a result.
So did we need to trade Malachi for the Hill trade? No, but that's not why we did it. Did we need to cut PapaG for the Hill trade? Yes.
(If you remember, there was speculation when the Malachi trade was announced that we would be cutting Caboclo after receiving him, because it would be cheaper than cutting Malachi. Clearly that speculation was wrong, but there was a time when people did think that the Malachi trade was to clear a roster spot for the Hill trade.)