There are two different paths for this team to take.
Terrence Ross - excellent option on drive and kicks. he has the ability to get his own shot. can rebound from the guard position
Landry Fields - good cutter, solid rebounder, capable defender. above average passer/facilitator
Ed Davis - would thrive on ducks ins - put backs. being the primary option when Lowry driving causes the defense to suck in. excellent help defender (allows wings to gamble a bit on passing lanes)
Jonas Valanciunas - can space the floor with this 15ft jumper, allow Ed to operate. developing post up game. excellent help defender (allows wings to gamble a bit on passing lanes)
who goes? Amir and DeMar
Terrence Ross - excellent 3pt shooter both as catch and shoot and coming off screens
DeMar DeRozan - excellent mid range coming off screens
Amir Johnson - screen and roll (20ft shot) rolls hard. Great chemistry with Jose.
Jonas Valanciunas - screen and roll (15ft shot) rolls hard. sets hard screens
The main difference between Jose and Kyle is who you go after in the trade and free agent market as well. Some likely targets (though we likely won't get them) for this summer would/should vary greatly depending on who runs the show.
For a small forward, if you keep Kyle you want Andre Igoudala. A two way player and facilitator from the wing position.
With Calderon you should aim for someone like Danny Granger. Good defender, great shooter.
PF for Kyle would benefit greatly from someone like Pau Gasol.
PF for Calderon someone like Millsap could save 10 million and be extremely useful.
In a game with the teams comprised of
Lowry/Ross/Iggy/Gasol/JV vs Calderon/Ross/Granger/Millsap/JV I honestly don't know who would win or who even really had an advantage. But the decision at the point needs to be made before the trade deadline. The days of just acquiring assets are over. A direction needs to be picked BEFORE we go looking for assets/talent upgrades, because it alters the kind of players that would thrive there. Think Lakers acquiring Steve Nash and Dwight Howard then running Princeton? Brooklyn acquires Crash, and Joe Johnson and then opts to play at a slow pace?
It sounds from a few sources like there is quite the internal debate going right now about who to keep? I don't think one way is more correct than another. I do think attempting to have the best of both worlds will ultimately dilute both directions resulting in yet more mediocrity.