1. Its in “Warsaw Ghetto diaries” by Hillel Seidman. An absolutely excellent book and first hand eyewitness account of life in the ghetto up to and including its destruction. I think it is out of print, but if you can get your hands on it, I highly recommend
Other eyewitness reported similar statements though I do not have those references off hand
2. I dont see were shopping pointed that out.
2&3 it depends on the circumstances. As you may know Rabbi Akiva DID support Bar Kochba. for most of Jewish history hiding made the most sense. you cant fight the czar’s army , every so often there is a little “demonstration” best thing to do is hide in basement wait it out until it passes. The holocaust was different. it wasn’t just a “little demonstration” You are making the same mistake that another poster (and many in our community) made namely “that the holocaust wasn’t all that “special”, and was merely a mid-20th century manifestation of what we have seen for many, many centuries (and millenia)” Just like during a pogrom the best bet was hiding in your basement for a few days until things quiet down, so too in 1940’s . some Gedolim made this mistake in the 40’s I am not for a second criticizing them, generally that was the best approach. But not this time .
Again look at Lodz where there was no uprising (not to the same extent at least) while I dont think exact statistics are easy to come by, I don’t think more Jews survived Lodz than Warsaw.