The glamour is explained in a pop up right after unlocking scholar an extra quest. (They should mention Selene there though in one of them, not sure this is happening right now.)

Regarding summoner, the shield and physick help with health, but not against interruptions. Your carby (soon to be bahamut phase) is basically just spamming long cast ruin. At lvl 90 long casts barely exist, so it's easy to forget (and if you haven't leveled new summoner or played low level dungeon you might have never experienced it.) Physick is also longcast. That said, I am not sure what level that duty was, hence no clue about the toolkit at that time. I remember the fight taking place in Mor Dhona, but when I googled that issue, I saw people mentioning another quest as well.