If you bat Rizzo lead off, you significantly reduce the amount of times he bats with runners on base. While I understand the idea that your best hitters bat 1,2, and 4, you also can get Zobrist and then bat him, Schwarber, and Rizzo 1/2/4. The idea behind Zobrist is he costs about an extra WAR a year than Starlin (Starlin is 10.5 AAV over the next four; Zobrist can be had for 15-16). If you can get Zobrist, you solve the lead-off problem AND you get a veteran in the clubhouse that fits in. Also, the Cubs retain the flexibility late game to say bring Baez in and play 2B, move Zobrist to LF and sit Kyle. Zobirst is not a move that can be made with Starlin staying on the roster, but he's probably a better value at 2B than Starlin. That's all you're measuring.
So now you have 20-25 million to address the hole you have in CF (but now you can sign a defensive guy like Jackson and live with the production he gives you from 7/9 in the order) and the rotation. Non tendering Wood gives you 30 million and that means you can maybe give Jackson a deal like 3/30 with eight million this year, 10 million next year, 2M/12M team option. To AJ, it's a guaranteed 2/20 and if he's worth the extra 10M in 2017, he still gets good money. To the Cubs, they move some money around and then maybe have enough to get an elite SP like Grienke or Cuteo.
Zobrist - 2B
Schwarber - LF
Bryant - 3B
Rizzo - 1B
Soler - RF
Montero - C
Russell - SS
P
Jackson - CF
Bench: Coghlan, Baez, Ross, Alcantra/Sczur/, Lastella
Rotation: Arrieta, Lester, FA Arm, Hammel, Hendricks
Bullpen: Rondon, Strop, Grimm, Richard (LHP), two of Edwards/Ramirez/Patton/Acevedo/Cook, Brothers/Rosccup (LHP)
Then you just keep affording raises with money as it opens. Arrieta eats up most of the money that they're giving him+EJax still and then you get Almora in CF in 2017/2018 with AJ out of the picture. Then you also replace Montero with Contreras in a few years, and finally you look to replace Hammel with either a young guy (Johnson, Underwood) or you look to FA for a value signing.
Also, signing Zobrist affords you the luxury of replacing any player in the lineup due to injury with Baez and/or Coghlan. That kind of top 10/11 depth is quite valuable as if the flexibility to move guys around to give them off days/match-up with opposing pitchers.