Good choice to name KK and Williams on the bench imo. As C pointed out it keeps the spirits up of the squad that have done all the work in recent months.
If there is injury queries over Mortimer and perhaps it is not as pressing that Hodkinson plays a full game with KK back in the mix, then I wouldn't be surprised to see Keating start under those conditions.
As for Williams, he should be great coming into the fray off teh bench as a forward at the 20 min mark, and doing his two 20 min stints either side of half time while the opposing pack are getting tired.