Are they wrong since the modal usages lack the fundamental conditional uses of the modals 'would' and 'could'? Not sure what you're asking. The correct sequence of tenses applies to conditionals as well as to non-conditionals.
1. We are all watching in a sort of stunned silence waiting to see if we would be asked for money or if we are simply his audience.
No conditional element present, thus 'will' is correct? Right? will is correct, but not for the reason that no conditional element is present. will is correct because will goes with are.
2. While I am reading it, I could not help being concerned about young people in this country.
Same here too. No conditional element present, so 'can' is correct? Right or wrong? Same here. can is correct because it goes with the present tense I am.
So, except those modal uses like politeness for 'would', most modal uses of 'would' and 'could' involve conditional nature. Right or wrong? It depends on the text you're reading. You may find a text that uses would or could in non-conditional contexts quite often.
Could you please answer these? -- case of a modal use for politeness. True.
Generally, will and can go with the present tense; would and could go with the past tense. It doesn't matter whether they are used in a conditional pattern or not.
Henry wants to know where he can find a good restaurant. / Henry wanted to know where he could find a good restaurant.
Kate needs a dress that will make her look slim. / Kate wanted a dress that would make her look slim.
If they sign the contract, they can take possession of the car immediately. / If they signed the contract, they could take possession of the car immediately.
If he hurries, he will arrive on time. / If he hurried, he would arrive on time.
_________________
Occasionally would and could go with the present tense, but these should be regarded as special cases. For example, take the idiom would like to:
I would like to buy the coat which is on sale.
The would and could of politeness are also usually combined with the present tense.
Could you please help me move these books which are lying on the floor?
CJ