I think they'd like to have Sullivan back; but they might have their eye on another, younger, C. Yet if PFF is right, they can get him for a year, pretty cheap.
I suspect they'll be looking at ILBs and OLBs. But I doubt the big names because they'll be either too old or too expensive. Besides, I think Wade wants very specific traits for these guys. And for ILBs it is run stuffing first, blitzing next, and coverage last. In fact, I suspect if the player was superb in run stuffing, a 2 down ILB opposite Barron might be sufficient at least for 2018. I really don't know which FA ILB that describes. Same for OLB. I think he wants run stuffing first, pass rushing second, coverage last. The name that comes to mind is Trent Murphy who to me is a younger faster Connor Barwin. Steady, smart, not spectacular.
They might also be looking for a big, run stuffing NT. I just don't think Wade's 3-4 works without a really stout NT. And with the Rams Dline roster this can be a 2 down player. So I don't think they'll be willing to pay the price an NT like Poe might get. I think Ngata could be a target if they can't get a younger guy they like at the right price.
So it might be the 2nd round of FA signings before the Rams get very involved.
I think the one thing that could happen is if they can't sign Watkins by day 1 of FA, they might go after a guy like Paul Richardson. In fact, I don't think the Rams will wait longer than the 2nd day of FA before they make a move at WR. It'll either be getting Watkins inked or somebody else. That position is just too important.