learn_russian | Writing and Speaking / Word Order and Intonation (Reply)

I have been trying to ken this for ages now and I don't care how much already-published information there is-- I need an answer from a "real, living" native Russian speaker who also knows English/linguistics/whatever:

I have learnt (as probably have most students of Russian) that word order in Russian plays a role in indicating the topic of a sentence and the focus-- i.e. the focus of the sentence is usually at the end of the sentence in Russian (whereas to compare with a sentence in English with "neutral" intonation, the focus is often at the front [but not always])

E.g. (very minimally):
В сад влетели птицы. - Birds flew into the garden.
Птицы влетели в сад. - Into the garden, there flew some birds. / Birds flew into the garden. / etc
Птицы в сад влетели. - The birds flew into the garden. / The birds entered the garden flying. / etc

However, I have also learnt that intonation (in Russian) also plays a role in indicating the "critical" information in a sentence (as contradictory as this will seem):

E.g. (with intonation marked somewhat graphically):
--------------------^_____
В сад влетели птицы. - Birds flew into the garden.
---------------^________
В сад влетели птицы. - Birds flew into the garden.
----^_______________
В сад влетели птицы. - Birds flew into the garden.
----' `______________
В сад влетели птицы? - Did the birds fly into the garden?
------------------------' `_
В сад влетели птицы? - Did the birds fly into the garden?

So, the first question would be: is it possible to indicate the critical information of an interrogative phrase using word order? e.g.:

В сад влетели птицы? - Did birds fly into the garden?
В сад птицы влетели? - Did the birds fly into the garden?

If so, how would the intonation pattern of these phrases be?

What's the difference in using intonation v. word order, or a even a combination of the above? Why is it that no matter which manner I utilise, people understand what exact information I'm requesting less than 50% of the time?

Finally, perhaps in relation to this: is the syntax/style of spoken Russian significantly different than written Russian?-- possibly partially for the fact that it is difficult to deduce the implied "intonation" of a written phrase? Does reading literary Russian (even non-artistic works such as newspaper articles) seem stilted or at least markedly literary even when spoken? If so, what are the exact differences between the two?

- Благодаря Бога Интернет