Hardy said in his presser that he doesnt see anyone being the "PG" or even "the lead guard". He said very clearly that they want to run "pairs" in the backcourt of players who complement each other and work well together. So I'm answering the question with the assumption that JC starts and we are talking about who he pairs up with (regardless of who is 1 or 2).
Now its obvious you need a player next to JC who is first and foremost defensively capable, and can also facilitate some for others since JC cannot be the only tablesetter.
Out of the guards we have, Dunn is the best guard we have in both of those areas. However I'm not saying he should automatically win the job since he didn't play that much with Lauri or Kessler last season, as he lead the 2nd unit and player with Dok, Samanic and KO more. So remains to be seen what level of chemistry he has with the starting frontcourt.
Its a training camp competition for sure as Hardy has also said, so all projections now are more or less wild guesses of who will win the job in the TC.