I finished all the Challenge Quests available to me. as predicted, I did die to the Gorgon fight, but who would've thought her Captured Goddess phase was her easiest? She kept bringing the party to 100% NP so Gorgon and Jeanne Alter kept pouring layer upon layer of curse onto her while Mash just kept making them all harder to kill.
The Quetsoquotl/ Medb fight wasn't as bad as I suspected, but it was bad. I wasn't expecting to win it first try, but I got through pretty good thanks to support Jack. Only lost two Servants the entire fight.
Also, Sanzang on offer, one pf the major Servants I want, and the gacha is being mean and won't gimme..