I want to see Brown at SG - it worked last year for a fairly decent sample size. I get that he has not reached his potential (at all), but he adds size and athleticism to the starting line-up. He should also get used to playing with the starters since he is well on his way to stardom.
I do think Crowder will get the nod, though. Not only has he proven himself as a starter, but he helps spread the floor and adds 'toughness.' And, not that it really matters, but it might ease Jae's anger with signing Hayward. Knowing that Brad still has trust in him might rejuvenate his play and make him happy with the signing. I would hate to see his reaction to backing up Hayward.
Fwiw, I think Smart would also make a solid starter, but agree that he is necessary to run the 2nd unit. For selfish reasons, I also prefer him to remain a back up so his value doesn't catapult. It worked with KO (clearly 'better' than Amir) who signed for a very reasonable deal.
This is all assuming Morris starts, btw, which I think is a foregone conclusion (again, see Amir starting)., but I don't expect huge minutes for him with Crowder, Tatum, and Hayward sliding to the 4 at times.