I only got past the karnak castle escape in my 1.130 on normal difficulty, so take this with a grain of salt, but..
Faris wound up being far too much of a hassle to use properly with the build I gave her. Since she's listed as STR/AGL on the class sheet I figured a heavy hitting physical attacker with dual-wield and X-Fight or TwinCut would be a good place to start, but she ended up dealing quite a bit less damage than Bartz and Lenna (I had intended Bartz to be an offensive caster and Lenna heals/buffs, but Lenna needed black mage's mass cast passive for multi-target buffs and bartz had cure from x-magic anyway so they ended up rather similar) due to the ease of targeting weaknesses with magic compared to constantly switching 2 weapons out, and with both crusader and time mage being unusable by Faris she couldn't learn pierce to help deal with this problem.
Or maybe I just need to stop trying to grab EVERYTHING in karnak escape. Seems like only a party of optimized heavy hitters can manage that cleanly which is probably complete overkill for the rest of the game.