1) yes, I know.... roughly equivalent is what I meant. I am aware of aspect ratio issue.
3) bad example. I should have said 110 film maybe.

Concerning 2.... My understanding is that definition of DOF itself relies on final print size and the viewing distance. So to aid my understanding, I was assuming one final print size and identical viewing distance. Why is it that bigger the film size, smaller the DOF? Why does this even matter when I'll be printing to the same size paper to compare? It became further confusing when I started to factor in equivalent focal length size adjusted to the film image size....

Can you help me explore the topic 2?