I think West is the more complete back for the system, i expect him to resume starting duties with Ware earning a few more carries. More in the mold of McCoy and Karlos rather than Langford/Forte. Just my guess.
I think Oliver has the best chance for long-term value. He'll get a couple of starts, and if he can put up Woodhead numbers the rest of the season then he could be a good flex play.
Hillman may get 2-3 starts, but the schedule isn't easy, and he's got potentially 2 other RBs to share with. He'll likely lose GL carries at least. And I think the job is Ball's when he gets back. Denver knows what they have in Hillman, and clearly they don't view him as a starter. I don't think Ball's problems have to do with talent - the O-line blocking just hasn't been there.
I'd go Oliver-Williams-Hillman for waivers.
I agree with you, I think Oliver looked great. Assuming he produces like he should against Oak then he's going to play going forward regardless of Matthews. He has value now and later IMO.