Learn English – difference between saying “Members are” and “All members are”

I agree that it sounds curiously redundant. The "of us" could be removed from any or all of these sentences, and the remainder would convey essentially the same meaning:

We are, all of us, in the grip of various philosophical assumptions, presuppositions, hypotheses, even theories, about the way the world is, and about what matters in life. (M. Rowlands)

We are all of us bound to work toward this end. (T. Roosevelt)

We are sculptures and recordings and movement and canvas stretched, and we are all of us works of art. (K. Curren)

I suppose the redundancy is intended emphasize or reiterate that whatever follows has some universal or all-inclusive quality - although the scope of that inclusiveness depends on the context:

Although our experiences are different we share a common heritage of oppression: we are, all of us, women. (Z. Dé Ishtar)

I would prefer to offset the "all of us" with commas, but as FumbleFingers pointed out, that seems to be a matter of personal preference.

Out of curiousity, I repeated variations of the "we are all of us" search, using "we will all of us" and "we are both of us," to see if those phrases were also found. Both turned up plenty of results, mixed with and without commas (and one made a rather humorous parenthetical exclusion to the inclusiveness of the verbiage):

We are both of us nice of temper; we are both apt to kindle, and warm of resentment. (H. Godwin)

We are, both of us, perfectly capable of taking all sorts of chances. (J. Katzenbach)

By then it will be too late. We will, all of us, have made our fortunes by then. (F. Norris)

My own prejudice is that we will all of us (except, let it be quickly admitted, personal injury lawyers) be better off under no-fault than under traditional tort liability. (H. Ross)

Both expressions are grammatical. The main difference between these two expressions is that the word what in "what questions are there?" is used as a determiner, whilst in "what are the questions there?" it plays the role of a pronoun.

They basically have the same meaning. However, the determiner the in the expression "what are the questions there?" suggests that the asker knows there are questions there but is not sure what they are.

"What are the questions there?"

expected response:

"The questions are ...."

And that is slightly different from using the determiner "what", which suggests that the asker has no knowledge about the subject.

"What questions are there?"

expected response:

"The questions are ...."

or

"There are no questions."