Hah... I just noticed a secret in Mist I missed my first two times through. How unobservant of me to never notice this place!
Oh, it leads to the Serpent Road, this might be one of the areas you've newly changed from the last version.
Well made it back through the Misty Mountains, this time I decided to throw caution to the wind, leveled up Rydia to 20, fought Scarmiglione and used Ifrit to defeat the Revenant, the Bio is strong, dealing 700 damage to Cecil because of his lack of magic defenses, but only 200-300 to the others, seemingly. It took several turns, but Scarmiglione 1 was defeated. Scarmiglione 2 was also quickly removed by Ifrit, though still dealing large chunks of damage with Quake.
I am now back up to Troia.