Yes, if Trump decides to debate, they will be epic. Two very different types of people, both energetic.
Christie will carve up DeSantis and take the establishment vote for himself. He's an a-hole but a vastly superior debater than DeSantis. Of course, all that will get him will be 20% of the vote.
Tim Scott or Pence will scoop up that small evangelical vote that doesn't care for Trump. Both are much more authentically Christian than DeSantis.
DeSantis will be out of the race by the end of the South Carolina primary.