niether..
No, It is neither toxic nor flammable.
Crushed ice would melt faster because it has more surface area, and it probably has a less density than regular uncrushed ice.
It is a mixture of the two.
Ice is frozen water while Ice cream is normally something resembling frozen custard. It has quite a high level of fat. There are may sorts of ice cream and thay all have different ingredients. Sorbet...
With big refrigeration units.