Which one is correct?

  1. I only knew her by look.
  2. I only knew her by sight.
    Which one is correct?
  3. It sounds incredible; it’s true though.
  4. It sounds incredible; it’s true yet.
    Which one is correct?
  5. The boss was not so severe as he must have been.
  6. The boss was not so severe as he might have been.
    Which one is correct?
  7. His resignation came as something a surprise.
  8. His resignation came as something of a surprise.
    Which one is correct?

Which do you think?

Beeesneees,
I furnish below my answers:

  1. I only knew her by look.
  2. It sounds incredible; it’s true though.
  3. The boss was not so severe as he might have been.
  4. His resignation came as something a surprise.
    Please comment.

“I furnish below my answers” is completely unnatural. Better to say "My answers are below"or “I provide my answers below.”

‘knew her by sight’ is the correct idiom. 1 is incorrect.

6 is incorrect ‘something of a surprise’.

You got (3) right.

Beeesneees,
What about #5?
Is it not correct?

It’s correct

Beeesneees,
You have answered as below:
‘“I furnish below my answers” is completely unnatural.’

  1. “Can he furnish the information to us?”
    Is this sentence wrong?

It’s unnatural. ‘Can he furnish us with the information?’ is better, but still uncommon.

Beeesneees,

  1. Can he provide us with the information.
  2. Can he provide the information to us.
    Which one is correct?

Can he provide us with the information?
Can he provide the information for us?