Paladin can heal and bard can fill in for healing sometimes, definitely go with what seems fun as opposed to party dynamics. Hopefully, even if your party is in need of healing, your dm will be a good one and work with you/that.
At the end of the day, it's likely going to be a collaborative story, so your part in the story needs to hold your attention, so whatever character tropes/types you like is a good basis to start.
Maybe make a list of types of characters or themes that interest you, then a list of races, then a list of classes and see what combinations make your imagination happy
The fact they've got a shapeshifter and a Tiefling Paladin (I mean, there's gotta be a story there?) and two Genasi.... I could either stick with the weird supernatural theme or be the lone muggle
My first character was based on kid Loki, in the sense that he kept wanting to do the right thing but was always a little sneaky about it and also a Tiefling in denial
if you're looking to just fill out what the team might be missing I'd say maybe another melee/tank since aside from the Paladin you don't really have anyone who's not going to run up on the opponents. Maybe the druid will but at low levels idk. Druids can heal too so I wouldn't worry that much about being a healer.
but there's the Divine Soul sorcerer if you do want to do some healing and not be a cleric. if you want to be a non-magic class but still want to kick ass, there's the monk or the barbarian...
I mean, I had similar dumb ideas that eventually led to ridiculous places. Like a Half-elf bard investigator type who eventually just became Spiderman Noir from into the Spiderverse.
I jus imagine this random guy standing next to the rogue who hulks out into lizard form and the guy just looks at the others “alright who else can do weird shit?”
we have a Tiefling Paladin, Two Fire Genasi: a bard and Druid-Baker, and a Human Rogue who can Jekyll and Hide shapeshift into a lizardfolk.