shiny ho-oh soft reset

Which, BTW, is NOT the same thing as saying that if you reset 4999 times after failing to get a shiny Ho-Oh, there's a 45% chance the next time.

There's no advice we can give except "good luck... you'll need it". It's completely random.
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Creator of Jay's Journey (see quote!)
"Game Series 1 is the best because it set the stage for better games!" - Nostalgia whores everywhere

Depends. How much do you like seeing a Ho-Oh with a light orange body, dark orange feather tips, and a white beak and tail?

Gameplay-wise, there is no difference between being shiny and not being shiny.
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Creator of Jay's Journey (see quote!)
"Game Series 1 is the best because it set the stage for better games!" - Nostalgia whores everywhere

Are the birds' data generated when you encounter them or when you talk to someone, like the Latis in R/S?

The only Pokemon whose data is generated "when you talk to someone" are the roaming legendaries, because they're the only ones you can encounter in the wild more than once, so they wanted to guarantee that they'd be the same every time. Ho-Oh is not a roaming legendary.
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Creator of Jay's Journey (see quote!)
"Game Series 1 is the best because it set the stage for better games!" - Nostalgia whores everywhere