You know, we might be able to add Cousins AND Hayward this year. That would enable us to make a run for the championship this year while ensuring we have Hayward's Bird Rights next year.
We would probably need to trade Brown, Johnson, Jerebko, and Olynyk (Brown would be redundant, anyway, with a commitment to a 26 year old Hayward while retaining Crowder; if we are making a championship run, we should stick with Crowder off the bench rather than Brown). We would likely have to stash Yabasule and/or Zizic. We would also presumably give up all but two of our draft picks the next four years, of course, since that combination of players alone is not getting you Cousins AND Hayward (although a combination of the players with our arsenal of first-round picks might get us there; heck, the Jazz might trade Brown straight-up for Hayward if they are certain Hayward is jumping ship next summer).
If we somehow pulled it off, here is a quick breakdown without any second round picks (perhaps we sign Jackson while stashing Bentil and Nader) and veterans who sign the minimum after we settle on our rookies (who knows, we might be able to attract someone like Ray Allen and/or Vince Carter since this would clearly be a top five team next year):
Horford $26,540,100
Cousins $16,784,031
Hayward $16,073,140
Bradley $8,269,663
Thomas $6,587,132
Crowder $6,500,000
Smart $3,578,880
Rozier $1,906,440
Young $1,825,200
Hunter $1,200,240
Mickey $1,200,000
Total $90,464,826