Are Reynaud or Kalkbrenner likely to be any better than Queta? If so, take one, but if not I think Flemming is more interesting based on scouting reports.
If the C's add Hugo and Flemming, they add two high energy multi-positional defenders. Of course this doesn't replace the loss of Jrue in Year 1, but in years 2 or 3 - maybe. Both seem to have upside and both seem to be players who will play NBA minutes just based on their motors and size.
C's have an array of offensive contributors (at full strength): JT, JB, DW, PP, Simons, Al (Sam if he's here; Baylor). Having more focus on D is a good direction. And Flemming looks to be a competent offensive player, and Hugo is young and may develop his shot.
Anyway - I feel like Flemming should be the pick.