Hmm... the players you mention are certainly possibilities. Of those, Kim might be the most tempting, since there is still a possibility that Mantei will return to the closer role. Trading Kim plus a bat for a lesser (but safer) closer and a hitting upgrade could work very well.
Of the others, McGriff is at a high right now; if you can package him with an arm for a star 1b, I'd do it. There's no telling when he'll return to mediocrity.
Prior is at a high right now, too, thanks to his excellent starts and the hype surrounding him. I like him, both for this season and for the future, but it may be worth asking around whether anyone is willing to pay a ridiculous price for him. Some of the offers for him thast I've seen are amazing.
I think you have a lot of options here. Just about any of those players can conceivably be upgraded (Pierre + arm for Ichiro, for instance). You should be able to make some pretty solid offers.