that is too expensive a platoon for DH. Trade one catcher.
Trade Carew. Not good fit for you park. I know you want someone to get on base to be HRd in but Carew is not the guy. There are lots of 1Bs you can pick up with high OBP and power. Carew can't field or run. HE just hits singles (granted, lots of them)
Phelps is a good replacement 1B late in season but too expensive for DH. Look for Kemp, Zisk, Incaviglia, Lonnie Smith etc... for DH (hopefullly one of your .75 guys has its good year and can be used to DH)
At 3B, are Horner, Hojo, Bonilla or Harrah available? Don't be afraid of using a 4 at 3B. Jacoby is not bad but I have seldom seen anyone play him.
I would consider trading Butler if you can get Davis, Kirby, Murphy, Dawson or even Gormon.
Fisk/Tettleton, Carew and Butler are very good and could be traded to someone in a pitcher park for some HR studs or pitchers.