Well, here was my thinking. You trade Brown + Smart + a pick, and you roll with Kyrie, Kawhi, Hayward, Tatum, and Horford next year. May require some other moves to stay under the tax, but that is one hell of a team.
After next year, you would expect both Kyrie and Kawhi to decline their option. However, both of them will probably only want to sign a 2 year deal so as to sign their next contract as 10 year players worth 35% of the cap. If you can convince both of them to sign 2 year deals, there would be a hefty tax bill in 2019/2020 as you have Kawhi and Kyrie making 30% of the cap on top of Hayward's 32.7 mill, and what is a likely to be picked up player option in Horford at 30.1 mill.
However, Horford is off the books the following year. Hayward is likely to pick up his 2020/2021 option, thus you are rolling with three max players in Kawhi, Kyrie, and Hayward.
Then, all three of those guys would be free agents that offseason, and Tatum would be up for his extension. That would be a wild offseason trying to figure out who the hell to give the money too.