1. Why is Iyov considered acceptable but other mussar or philosophic works are still forbidden? It's not like Iyov has anything to do with the Churban or aveilut. Just because part of the story involves the deaths of his family members?

2. You're allowed to go through a river up to your neck to get to or from a torah teacher, or to protect your fruit from loss.
Is swimming mentioned anywhere in Tanach? Not walking in water but actual swimming?

You mean like paroah in the nile?

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the chumash says he actually swam in the nile? which passuk?

The passuk just says he went out to the water.

What about in melachim the story of naaman?

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Floating is...

Where?

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Noach, Moshe, Yonah, anytime boats are mentioned...

And whenever it talks about animals or people drinking water it mentions the word mayim.

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ויצא יצחק לשוח בשדה

Na'aman immersed in the river. That's not swimming. By swimming, I mean propelling oneself in the water without mechanical aid to get from one place to another.