If Boston ends up with 2 of Porter, Bagley, Ayton, Mamba, or Doncic, I just don't see the team bringing back Thomas.
That said, I'd like to think Boston trades those picks for Anthony Davis (something like both picks and Morris for salary) and you couple that with the trade later this summer of Thomas, Crowder, Rozier for Irving leaves you with a team of:
C - Horford, Zizic, Theis
PF - Davis, Tatum, Yabu
SF - Hayward, Vet Min, Ojeleye
SG - Brown, Vet Min, Vet Min
PG - Irving, Smart, Vet Min
So the basic 8 man playoff rotation of Horford, Davis, Hayward, Brown, Irving, Smart, Tatum, and Zizic.