Kennedy>Lester.
Lester's career best WHIP was 1.15 in 2005 in AA. Other than that, he has been over 1.3 in his MiLB career. Over his major league career, he has made 25 starts, compiling a WHIP of 1.57 in that time. Over his MiLB career, he has compiled a WHIP of 1.31. Both are poor when considering the type of pitcher Lester is. I know a lot of people want to give him tons of credit in terms of his SR due to the cancer, and I love the guy for his determination, but lets be honest here. He's a high 80s-low 90s pitcher with shaky control. He allows a TON of baserunners and through nothing other than luck, he has avoided the major disaster. I expect his K rate to stay respectable, but if he continues to walk 4+ per 9IP, he will be burned.
Kennedy OTOH, is a full yr younger and doesnt have the health concerns that go along with Lester. He throws high 80s to low 90s, but is known as a total control freak. In his only minor league season, he walked 1 per 9 less than Lester did without giving up the hits that Lester did. Also, throughout all levels of the minors, Kennedy maintained a near 9K/9IP rate. Plus, his stellar debut in the majors also speaks to his ability. He doesnt have the breaking ball that Lester has, but Lester doesnt have the changeup or the fastball location that kennedy does. All told, Kennedy has a slight edge IMO which will grow if Lester doesnt consistently locate this upcoming yr.
Melky>Crisp in terms of age, ceiling, and potential. Melky was given the CF job in May. From May 1 to the end of August he hit .313 with a .810+OPS. September was uncharacteristically bad for him (18 for 100). That being said, he is a solid defensive CFer with good range and a great arm. 14 assists speaks to his arm ability. Crisp is the better ranged OFer and the better baserunner. But in terms of ceiling, Crisp is likely at his while Melky has more room to project.
Tabata=Lowrie. Lowrie is ready now. He could be a solid 2b for many yrs and will be a good OBP bet due to his good eye. That being said, Tabata played High A ball all season with a cyst in his wrist that caused him significant pain. He has had surgery to fix this problem. Even with this hindrance, he hit over .300, had an OBP of .371 and stole 15 bases. He has a great arm and the kicker is, he just turned 19. In terms of right now, Lowrie is the right guy, but nobody can deny Tabata's tools. And with the possibility of him being totally healthy and adding to his power potential, he might end up being the jewel of any prospective deal. I give Lowrie a slight edge due to his position and his proximity to the bigs.
In terms of Horne vs Masterson. Nobody will doubt Masterson's ability. He's 6'6" and throws gas. That being said, Horne has proven he can be both a sinkerballer and a strikeout pitcher. And prior to a late season swoon, he was absolutely dominant with a WHIP below 1.2. But most of the argument here harkens to their projectability. Horne made major strides with his sinker and changeup this season. Enough so that he is in the picture as a SP. Masterson, OTOH, has been a reliever in the eyes of most scouting sites since being drafted and he has done nothing to change that. Will Masterson be a better reliever than Horne will be as a starter? Probably. But that being said, an above average starter is worth more than a good reliever these days.