I dont know bout the best, but I usually can slap together a WC team no problem.
In pitcher parks, I live and die by a cheap 6 or 7 man rotation. With that, I do like what you started with your bullben. Kimbrel is gold. Koji, may hafta go. There are cheaper options, that will do the same, some, with an R2 rating, that your pen is sorely lacking. My bullpens are slightly cheaper than yours, by 1-2 mill. 1 stud closer. 1 guy thats an r2, in the 3-4 range, I try for an r2, but will take an r1 in the 2.5 range. and then two specialist, one for each side, usually no more than .8 each.
Def up the middle. That cannot be said more, or loud enough. A Barney or Galvis at 2nd, and something like a Crawford at SS, if I am looking to save money. a 1e24, will yield bout the same runs as a 2e16 or so.
Anytime, you can get a - arm in the OF, it cant be a bad thing.
Your wasting money at Catcher. Mauer can go both ways, and is a 3 gamer. Which means he will only miss 9 or so games a year. Let him bat both ways, dump that other guy, and save bout 1.75 mil finding a cheaper back up, instead of platooning who ya have.
In general, the team is not that far off from something I would attempt. I like Votto, but be prepaired to be without him for 30-45 games. On my one team that is 1 game up for the WC, I just lost him for 15 at the transaction deadline. I also have Moss on that team, so i dropped Joey, and grabbed Choo.
Natural power is something else ya want. Somebody that can just hit a HR anywhere. On the team with Votto and Moss, I also have Longoria. And, was surper lucky (so far!) he has only missed 15 games. While you want to win at your place, you need to be competitive in HR parks too.
I dont wanna give up the farm, but will toss a few names out there that do well for me in small ball parks. Brad Lincoln. i have him on the WC team from above, he's 18-5 with a 3.07 ERA. Wellington Castillo. Card says 5L, but can go both ways easily. David murphy in LF . And an uber cheap effective RP is Brad brach, tho he is only an r1.
Hope some of this was helpful, I hafta run to work.