I like 30-40m sprints coming off a curve into the straight for establishing solid cross-over quick feet technique(on ice) with fellow hockey players. The curve work in both directions will provide a reference point in the mind of solid slow feeling technically sound crossovers which look very fast on the ice to the outside observer.
As for ankle mobilty i go with jump rope after inseason ice sessions for 12 - 15 minutes(8-10 reps of 30-40 secs separated with 1 min recoveries). 3-4 X a week, again after the ice session.