OOC: They changed how AoO work for 5th edition, I briefly outlined it in the OOC thread but if you move into melee range you won't provoke one. So if you want to to P12 you'll be fine.
As for Intimidating in combat, I don't believe there's specific rules for it so it falls under "What DM says goes". And this definitely seems like a context where it'll work.
I'm gonna give the goblin a chance to not soil his breeches *rolls behind metaphorical DM screen* You know what that's a funny enough roll to show off:
Goblin wisdom save vs intimidation: 1D20 - 1 = -1 = 0
So yeah consider that goblin Very Intimidated. G3 now has the Frightened condition (A frightened creature has disadvantage on Ability Checks and Attack rolls while the source of its fear is within line of sight. The creature can’t willingly move closer to the source of its fear.) and will flee on its next turn.
IC: Something about your words and appearance inspires utter terror in the goblin bandit, even more than might be expected of someone facing down an angry armored paladin and their equally dangerous allies. No this Goblin looks at you as though you were an avenging angel or a vengeful spirit with an army of the damned at your back.
All the fight drains out of the Goblin, it looks panicked. It begins muttering in a rapidly in a language none of you speak (probably its native goblin tongue) but keeps repeating one word that clearly isn't a goblin word. "Delian!" Whatever it means the Goblin is clearly using it to refer to Celestine.
The human bandit has judged that things have gone down the crapper and top priority is getting out of here. He cautiously moves out of Evan's reach and moves away, his flight slowed by the effects of Sariel's spells.
OOC: Human bandit uses a disengage action to be able to move without provoking an attack of opportunity and moves to K15 since his movement is currently reduced by 10ft.
Celestine and Sariel, roll me a History check.