I'd be more interested in " 'A fateful encounter' " than the 6 IVs. Based on the verbage, the Bulbasaur was clearly transfered through PokeBank from OR/AS to get to Sun/Moon. However.... The use of "A fateful encounter" is Nintendo's/GF's way of denoting a Pokemon came from a giveaway. What with the 20th anniversary giveaways, I don't recall there being a Shiny HA Bulbasaur giveaway. This is made further suspicious by the fact that is has no Ribbons. Most giveaway Pokemon have at least 1 Ribbon.
6 IV Pokemon are in no way an indication of a hacked Pokemon. I have already bred over a dozen 6 IV Alolan Vulpix. Granted, I'm using a 6 IV Ditto from r/BreedingDittos that is, in all likelihood, the clone of a hacked Pokemon. But the fact is that it's only a shortcut. It is entirely possible, if incredibly tedious, to breed for 6 IVs without already having 6 IVs.
The red star simply means that the Pokemon is Shiny. There are a handful of Pokemon where it is actually quite difficult to tell if it is Shiny or not. The red star is just a UI element confirming that. And Chlorophyll is simply Bulbasaur's Hidden Ability. It can be obtained from X/Y's Friend Safari, which can then, in turn, be bred for in the Daycare.
Knowing nothing but Hidden Power is... odd... but not at all an indication of anything. It just means that it was taken to the Move Deleter and anything else it knew was deleted. And having all 31's for IVs produces the Dark type Hidden Power, so we're good there too.