Rams haven't even begun, in any real sense, to put together their D for 2018.
Assuming Joyner and NRC are re-signed (NRC was a Phillip's pick and played awfully well), then I see FA pick up starters at one OLB (although it could be Barwin, again), ILB (my bet is Bowman or Clay Matthews), and Ngata at NT (he'd be my target).
Rams have DT/DE coming out their ears.
I suspect that Ekubam will either be a starter or play at least 50% of the D snaps.
I also suspect that Littleton will have an increased role both inside and outside.
What is needed isn't pass rush help (even with Quinn gone, Longacre is capable of applying good QB pressure), it is run stop help. And that begins at NT. Next stop: ILB. I may not have the players right (Ngata and Bowman or Matthews) but those two positions' starters will almost certainly be FAs.