I do not think that any trade ainge achieves through draft this year garanties a playoff spot next year...
I do not think that the nets are playoff team..
i do not think that the mavs will be better next year with an aging dirk..
so..those picks have real value.. do not trade them
No.
If you can land an all-star by trading those picks, then you do it!
Depends on the All-Star.

I'd be very cautious about dealing those picks. There is a
mighty good chance that all 3 picks - Dallas, NJ and Boston - are top 20. There's a better than average chance that one of these ends up top 10. It's of course pure speculation, and the draft, retirements, injuries, etc. all will alter how things shake out. But at this stage, all 3 teams look like they're marginal playoff contenders. Odds are that 3 marginal playoff teams all won't make the playoffs. It could be like this year in that all 3 make the playoffs and the Cs are picking 15, 16 and 21. But I think it's hard to imagine that it would be any worse than that and it could be significantly better.