First of all, Castillo has been HORRIBLE against the run. Among 3-4 DEs, he was second to last against it in the ENTIRE LEAGUE. Last season, both Castillo and Cesaire only had one sack each with one QB hit each. Now Castillo had far more pressures (14 to 8) but only had 2 more tackles than Cesaire. On the whole, Cesaire actually graded out slightly better than Castillo, but Castillo was the better pass rusher and Cesaire was the better run-stopper according to the internal data. So, they have similar rating OVRs, but are rated quite differently with their attributes.
The rating desparity between the kickers is because Novak was brought in on April 3rd to provide kicking duties while Kaeding was injured with a groin pull. Novak has also not played since 2008, so his rating will need to be updated and will drop during camp while Kaeding recovers. I mentioned the FA part in a previous post.