Assuming Italy beat Costa Rica today...
Italy are still not guaranteed to go through. They could still go out on goal difference if they lose to Uruguay and Costa Rica beat England. Therfore italy would be unlikely to rest all their best players for a match in which they might go out if they lose.
A draw would be good enough for Italy but not for Uruguay if Costa Rica were to beat England. Therefore you wouldn't have a situation where both teams would be playing out a draw like Germany v Austria in 1982.
Uruguay need to play for a win and playing for a draw would be a dangerous plan for Italy.
The biggest danger of any settling IMO would be if England were say 4-0 up against Costa Rica at half time, and a draw would then suit both Uruguay and Italy.
So basically England need to keep Uruguay guessing, let Costa Rica score an early goal and then wait till about 85 minutes before they score 3 back. Simples!