In my opinion...
Most likely- Talib. Unless his performance falls off a cliff this year there's no reason he would not be back in 2019.
Least likely- Suh. I think this was understood as a true one-year relationship by both sides.
TBD- Whitworth. Personally I think it's a little less than 50/50 he returns for 2019. 38 year-old OL are not common and the deal was constructed to be a two-year deal. Rams save $10.75M in 2019 if he retires or they release him.
Joyner- I'm in the minority in feeling he could get tagged again in 2019 but we'll see.
Saffold- I think it's 60/40 he returns. I think he'd want to stay and finish as a Ram. Hopefully they could agree to a moderate 2 year extension.