If you really had no issue trading guys that signed as free agents, I would in an optimal world do something like this (and these trades are rumored or reasonable value). This is how you build around Tatum and Brown and build a realistic contender in the future and still have an excellent team next year
Trade #1 - Smart, 14 for 2
Trade #2 - Hayward, Langford, Edwards, 24, 30 for Oladipo, Turner
Trade #3 - Walker, Fall for Rubio, Bridges, Oubre, 10
Team next year (cut Poirier, Green)
PG - Rubio, Halliburton (with 10), Wanamaker
SG - Oladipo, Ball (with 2), Bridges
SF - Brown, Oubre, Ojeleye
PF - Tatum, Williams, Williams
C - Turner, Theis, Kanter