I know Russian tanks had large white crosses painted on top of the turrets for easy identification late in the war.Did this hold true for other Allied nations?
No. Rather, by the end of the war the Allies were more and more careful in using Allied Stars for recognition by friendly forces because the large white circle-with-star attracted way too accurate enemy fire. I believe that in 1945 very few Allied armoured units still had those big stars on their tanks.
The large white crosses/stripes on Soviet armour were there to prevent British and American aircraft from attacking them. They were only used on Soviet armour, at least to my knowledge.
