Originally Posted by
Nestama
Ivalice has a pretty neat timeline. I recommend you read it.
Yoshi-P could have said either FFXII, or FFT to give players an idea. FFTA and A2's 'Grimoire World' takes place roughly around XII's time, whereas FFT takes place centuries later where Moogles are extinct and other races have disappeared (either moved out of Ivalice, or were also wiped out). I think St. Ivalice (reminder: real world of FFTA and FFTA2) also takes place many centuries after FFT. Since Marche reacted in surprise to a Bangaa's appearance, it's safe to say they don't exist any more.
You can buy Final Fantasy Tactics Advance on Nintendo's e-Shop.
If Viera were indeed spirited away, then for them to appear in Hydaelyn would either require a rewriting of the world/lore book (because how would no one know of their existence for thousands of years? especially when some Viera are wanderers), or they all appear all at once (probably causing a cataclysm because that's a lot of people appearing suddenly. Hydaelyn is a fragile lass) for the Ivalice raid.