Lincoln was a well known religious sceptic and would possibly have been an Atheist if he had lived in the modern age. As Gore Vidal put it in
Lincoln, when Lincoln is asked if the rumours about him not being a proper Christian and churchgoer were true, he replied "Founded, I'm afraid, on my
impropriety and chronic absence from church." Which would be quite a remarkable position for a president, even today.
Vidal's book is a historical novel, but it's pretty meticulously researched so I personally give it some credence.
Einstein was an Agnostic and quite damning of organised religion, including Judaism.
Religious views of Albert Einstein - Wikipedia, the free encyclopedia