I'd go with LaRoche and Arroyo
people like to forget with LaRoche, in a bad hitters park in Atlanta he blasted 32 HR. On top of that people see him as a natural platoon player, and this just isn't the case if you look at his righty/lefty splits. I'm a big believer in second half rebounds, and after an atrocious start LaRoche did that to get to 22 HR. He's always been a slow starter, but I think he will be a little better than he was last year to start the year, and would pencil him in for 25 HR and 80 RBI. Butler is more of a question mark to me, and althoug hthe streakiness is there, who cares.
Also, don't listen to these people talking about Jay Bruce at utility. He won't play, don't get your hopes up. Dusty Baker signed a guy like Corey Patterson whose only natural position is CF, to block Bruce. He hates the young guys, and it can be implied from his former and current demeanor that Bruce is the 4TH CF they want to use behind Patterson/Freel/Hopper. If he tears it up a little longer in the minors he will have no choice but to bring him up, but even then his playing time will be sporadic at best. What you do is you keep him on your bench and enjoy the fact that your INF spot is covered.
Also, LaRoche is a better hitter than Johnson. When you factor out position scarcity and just look at the career stat lines it would be hard for me not to go with LaRoche. Keep everything the way it is, it looks fine expect maybe a little bit of a quesiton mark at C.
Thanks to Alec03 for the awesome sig