Nobody will trade the ones you've listed even if you did trade the farm and then some. So, in reality, you can only trade the farm for blue chip prospects with some type of risk.
Yes Harrison has not shown he can be the defensive player, but the guy is athletic and can flat score. You can teach defense, but you cannot teach a skillset. I would trade up
Barnes looks like marvin williams 2.0 I dont like his approach mentally, hes stiff with his movements and with his 2 years in college he hasnt impressed me.