Welcome aboard, MikeeDee!
You've got a tough call there. Your top six seem pretty clear (and very good), but the final keeper isn't.
I don't think I'd keep Phillips, who may not have much of an impact next season. If you believe in him, you can certainly redraft him. The remaining three players are all gambles in one way or another.
Kendall's stats were nothing to right home about last year - even for a catcher. If next year turns into a rerun of 2002, he's not worth it. Kendall has so much desire to succeed, however, that it wouldn't surprise me if he were able to turn things around again (minus a couple steals, which won't hurt you very much in a straight points league)...
Hill is also an interesting player, but he'll need time to develop. Unless your league is very deep, you'll be able to redraft him later.
Blalock probably has the greatest potential of any of these guys, but there's no guarantee he'll even be in the majors all season. At the moment, it isn't even certain what position he would play.
I think there are two ways to play this. If you're looking to build for the future, go with Blalock in the hopes that he'll turn into a stud, but be aware that anything he gives you this year is gravy. Personall, though, I'd go with Kendall and pick up some solid prospects later on. This year, there will be enough high-upside youngsters to go around. Your keepers are excellent, so unless this is a very small league you should be in the hunt. Kendall will at least be average at the shallowest position, and possibly quite a bit more.