For a DnD campaign, also long post forgive me.

The campaign leads up to the party venturing into some of the planes and stopping a cult from corrupting and disrupting the planes. (What I have so far is the cult of Vecna drawing energy from these planes in hopes of raising their Lord. This of course does not have to be final but it's the best I've got.) Anywho I need quests and mini arcs to level the party up before they start entering the planes. I'd like some ideas relating to their backstories because those are always great.

The Bard is a Duergar (underground dwelling dwarf), who was banished from the underdark for being a nuisance, his instrument of choice is the konis hupen (I mean why not right) if youre confused here it is, its refering to the horn suit. https://youtu.be/PcRyjkYdDxM

The Monk is a wood elf who was cast out of his village because he was seen as a bad omen due to his unnatural silver/gray eye color.

The Arcane Trickster halfling gave no backstory. I'd really love to find something I could make for him. Maybe a heist of sorts?

The High Elf paladin wanted to resemble his blood elf paladin in World of Warcraft, so he's flashy and acts very vainly. Claims his family owns a bank in a major city, hit on a dragon in a humanoid form disguise in the first session we played (we were playing LMOP, he's the only player keeping his original character)

I'm grateful for any and all advice I receive, the fact that you read this and gave me the time of day is wonderful.