I upgraded my GM's emotional intelligence skills, and got Gasol accept my offer (5.2M + 5.4M Player Option - 6th man role).
It also turned out that Rice agreed to my offer too.
I decided not to trade anyone, so my rotation for the 15/16 season looks like that:
Wall/Smart
Beal/Rice/Neal
Porter/Ariza
Nene/Booker/P.Young
Gortat/Gasol
+ Larkin as the 13th guy in the team.
Meanwhile LeBron signed with Philly, and Melo with the Jazz.
All my players are healthy and I am 2-0 in the season right now, beating the Pistons and the 76ers, both very easy games.
Thanks guys for the suggestions!