Myers or peralta. I wouldn't drop hellickson at all. Cashner is a nice addition, but you don't know how he'll transition to the majors, so don't drop a pitcher it will leave you more vulnerable than dropping a hitter. I would definitely start plouffe over peralta with his HR potential and contact rate. Myers doesn't have much value simply because he is the houston astros closer. You can also get by with having 3 closers.
2)MYERS or try to trade peralta and include myers in the deal for 1 player.