You're right on with just about all of them.
Jackson is nothing more than a run-stopper with absolutely no pass rush ability and can't get on the field on 3rd down.
Dorsey is about the same thing as Jackson, only he's injury prone. Both he and Jackson should be gone next year.
Poe wasn't terrible for a rookie, but we'll see if he gets better next year. He played a lot of snaps iirc. I wouldn't be terribly upset if we traded him, but we would be thin on DL depth if we did.
Hali wasn't nearly as good this last year and I do think he's lost a step, but he should be good for about 10 sacks a year for the next few.
DJ was an underachiever, but ever since he started playing with more intensity, rather than just relying on talent, he's been one of the best ILBs in the league. He used to have trouble taking on blocks, and that was mostly due to a lack of intensity. I have no doubt he could handle Mike LB in the 4-3.
Houston is a pure pass rusher, much like Von Miller. He does have the ability to stop the run and shows great lateral quickness on outside runs and boot legs. His issue is tha the disappears at times in games. The guy has the potential to be elite in this league.
Hope this helps!