the REALLY big questions

Philosophy should at all times aim at answers. Whether she finds it, is irrelevant. But the direction of the endeavour must always be the answer.

I agree that should be the aim. I would only caution there are places philosophy may or may not be able to go with her logic and her language and her knowledge. For example:

Does chocolate ice cream taste better than vanilla?
Is Mozart a better composer than Beethoven?
Are liberals more prescient than conservatives?
Is abortion immoral?
What is meaning of art?

Indeed, in this respect even the smaller questions can be truly baffling.

I haven't read any Russell so far, but if he said philosophy is "not for the sake of any definite answers to its questions since no definite answers can, as a rule, be known to be true, but rather for the sake of the questions themselves", I disagree. Philosophy should at all times aim at answers. Whether she finds it, is irrelevant. But the direction of the endeavour must always be the answer.

Note, Russell mentioned 'definite' (i.e. God given) answers, not general answers to philosophical questions.

In the ordinary sense, all human beings are naturally programmed by evolution to seek answers as a default.
As such, in everything (including philosophizing) we do, the first aim is for the answers.

However in philosophizing (especially on the big questions), we need not follow the default as there are dangers in being too answer-centered, e.g. complacency, bigotry and dogmatism.
A question-ended philosophical quest is more effective to prevent dogmatism and open up opportunities for the expansion of one's knowledge.

that we even know so much about our in fact humble place in the world is because of scientific and rational enquiry. the critique that "rational thought itself simply implodes into the philosophical equivalent of a Black Hole" rests itself on the outcomes of rational enquiry.

"so much" is vague and very relative as we do not know the size of the 'whole'.
This is why focusing on the 'questioning' aspect is very important in philosophy. Continual questioning will enable us to expand our knowledge toward the whole, regardless of not knowing whatever the whole is.
Btw, even science expects its theories to be falsifiable and improved.
I noticed in many scientific papers, after the presentation of the conclusions, there are always provision for further questions to be explored.

Does chocolate ice cream taste better than vanilla?

Universally and unambiguously chocolate, but that is rather obvious

On a more serious note: There is indeed the danger to impose the philosopher's views on free individuals. However, what about, e.g. "The preferred taste of ice cream is not a universal value."

Does chocolate ice cream taste better than vanilla?

Universally and unambiguously chocolate, but that is rather obvious

Actually, it's not. I've had some pretty damned good vanila ice cream...

I think for the sake of philosophy and the preservation of the human specie, the majority of human beings should ponder the 'big' questions listed in the OP.

On this, I refer to Russell:

"
Thus, to sum up our discussion of the value of philosophy;
Philosophy is to be studied, not for the sake of any definite answers to its questions since no definite answers can, as a rule, be known to be true, but rather for the sake of the questions themselves;
because these questions enlarge our conception of what is possible, enrich our intellectual imagination and diminish the dogmatic assurance which closes the mind against speculation;
but above all because, through the greatness of the universe which philosophy contemplates, the mind also is rendered great, and becomes capable of that union with the universe which constitutes its highest good.
"
Russell, Chap XV, Problem of Philosophy.

Then a bigger question is, What makes us better question askers? Do we agree that hubris weakens our inquiry, and openness improves it? How about efforts to precisely define terms? While our answers will always fall short, perhaps as we adhere more closely to what we have learned makes us less fallacious in our argument, we'll get closer.

Axiomatically, You can't play the game if you don't know the rules.

Note that I am posting this because what I have read so far implies a great deal of respect for the rules. Just wanting to affirm that this is a good idea.

Keith, if you really believe those answers to the questions, why are you interested in philosophy? How can you be?

I'm not trying to imply anything, I genuinely want to know, because many philosophers throughout history were like you, yet they continued with lower orders of philosophy even though they had no reason to.

Technically, the word "exist" means "out of what is." It presupposes some "isness" as an unknowable given, and then says, "given this stuff that 'is,' what about stuff that comes from it?" Now, the god hypothesis contains the great "I am" quote, where the god, Jehovah, puts mankind in his place by saying that He "is," and all we are capable of knowing is what "exists," what comes from Him. Thinking about things that are too great for one is a part of hubris. It is good to want to know such things. I hope my algebra students want to know calculus. But, I do not encourage them to study calculus, until they have passed my algebra tests.

Philosophy itself technically means, "a brotherly love for wisdom." It begins by leading the would be philosopher to get precise about what words mean, words like love, brotherly, and wisdom. It asserts (e.g. in learning geometry and algebra), that it is unwise (a-philosophical) to get ahead of this business of precise definitions.

As for me, in my desire to know the answers to these great questions, the anti-hubris approach is to first find out who is the smartest authority available, and ask them. Many say that this God-person is most likely to have the best answers, and that He is handy, but expensive, to interview, or study under. "Seek Him with all your might," they say, and you will find Him, and can ask Him to explain it all. So far, I have found no-one, nor any report of anyone, who has paid the requisite price, and not "found" Him. And then spoken on the topics raised here as if they knew something more than usual.

Wisdom is defined as a plan that yields satisfying results. Learning all you can about definition, and love, and brotherhood I recommend as wise prerequisites to getting satisfying answers to these questions.