1, 2 are Jewish.
#2 is just not a very observant Jews. But still Jewish.
Note sure by what you mean by #3, but if you mean they converted, then they are Jewish.
It’s not hard: if your mother is Jewish at the time of your birth, you are Jewish. If you have an Orthodox conversion, you are Jewish.
Nothing on Earth can change that.
Nothing one does can change that.
RE: 1, 2 are Jewish. #2 is just not a very observant Jews. But still Jewish.
I think you mean #1 is just not a very observant Jew. BORN JEW, DOES NOT FOLLOW THE LAW OF MOSES
RE: Note sure by what you mean by #3, but if you mean they converted, then they are Jewish
Yes, that’s what I mean. A Chinese or African who converts to Judaism for instance, are considered Jewish.
The issue then is those who are at #1. Whose Parents are both Jewish but are not observant Jews. So, if such Jew became atheists, they are still Jewish, right?