A Frostbolt Crit or Ice Lance Crit should break the Freeze, correct? Whichever hits first should break the the Freeze, correct?
It doesn't matter that the Lance hits 1/100th of a second after the Bolt, if the Bolt hit first and crit, then there should be no Freeze for the Lance to take advantage of. The only possible way that a Shatter combo should be "technically" allowed would be if both Frostbolt and Icelance hit at the exact same moment, and honestly it seems a little ridiculous to think there isn't at least a fraction of a second in between when they hit.
All abilities are calculated with the effects when the cast completed. This is why you can shadow bolt as a trinket effect wears off (active when cast finishes, inactive when it lands), and still get the full effect from it. It also stops you from being able to pop a trinket during the travel time, and boost an attack already going through. This is a basic game mechanic, and a shatter combo takes advantage of it, but does not exploit it.
Drinking is something that, by in game definition, can only be done out of combat. Healing puts you into combat. Exploiting the "lag time" between when you can start a 2nd cast and the first one finishes as of 2.2? allows you to drink while in combat. This is not a basic game mechanic.