the traditional Polish 31st oct?
Nothing. The holiday is November 1 and to a muuuucccchhhh lesser extent November 2. October 31 doesn't enter into the Polish system at all.
November 1 All saints day (though celebrated like all souls day)
November 2 All souls day (barely observed)
It used to be
October 31 - eve of all saints/souls day
November 1 - all souls/saints day
Poland dumped the first because it's fun and Poles think holidays have to be dreary and religious, Americans dumped the second because the British already had