Did everyone picked one of the factions? It would probably makes things easier in the matters of getting together.
I didn't pick one of the factions but the church of Hoar is one-stepped removed from the church of Tyr whom is the patron of the Order of the Gauntlet so I'd get on well enough with both the Order and, to a lesser extent, The Knights of Samular.
Before all that, while you all have your reasons and backgrounds ready to go, you do need to form yourselves into something of a party. Please take a small bit of time here to discuss how you six have met and why you're willing to travel together. I really dislike spending the time in game arguing through the whole "getting to know you" period, and feel this will be much smoother.
Okay let's get to work on this then. I'm going to throw out some basic ideas about why Iados would be working with various people in the group.
Hexion: Okay this one is brutally simple. Iados wants to find and 'talk' to the fire cultists. Hexion is a recent drop out from such a cult. They may not be the same people who burned down that village but it's just too much of a coincidence to pass up. They two probably met while Iados was in his 'recovering and plotting' phase and, upon learning of the elf's history he would have all but press-ganged him into serving as a guide to track them down. Personally Hexion would get on his every nerve with his happy-go-lucky attribute and inability to stay focused but the paladin would put up with his... eccentricities for the sake of the knowledge he possesses.
Dev Remming: Iados knows of the Lord's Alliance and the good work they accomplish across the Sword Coast. While that doesn't mean he even remotely likes Dev (for the record he does not) the fighter has a decent pedigree behind him so that will give him some breathing room. So long as he keeps his mouth shut about his stories - I can smell lies and you reek to high heaven. That said you are out hunting bandits and Iados is a Paladin. While it isn't his primary focus his oaths prevent him from ignoring such a situation. If helping with the bandits gives him another sword-arm to help in taking down the cultists all the better.
Luka von Stipplewitz: ...aasimars. Urgh. Bards. Urgh. Friendly outgoing type believing in the innate good in all things. Urgh. You and me are going to get on like a house on fire. That said assuming you're out on some quest for good the paladin would offer your his blade - it's in his contract after all. You are working with the Harpers I see which is... nice I guess? What plot hook did you end up taking? Honestly it might be easier to attach yourself to someone else in the group and have our relationship being that off 'people who happen to know each other'. Hexion would be a good bet as I pretty much have to stick with them, what with lacking any other leads right now.
Obed Olmstead: Hey vengeance buddies! You're out to kill someone, I'm out to kill someone what's not to love? On a more serious note though if there is a guy out there blasting ships and you intend to stop him Iados would offer his blade. Especially if you happen to know the guy is related to some kind of water cult. That there is both a water and fire cult would be suspicious to say the least and would definitely be something I'd look into - worst case scenario I kill a bunch of cultists, best case I find a link between the two. Though once again 'boisterous joy of a sailor' would probably rub he the wrong way - I'd prefer you while you're in one of your moods.
Kitar: Let's just be glad you're a member of the Order of the Gauntlet and thus only one-step removed from me. I know the Orders works and have a healthy respect for them even if as an individual I'd despise you. Arrogant fantasy racists ("bird people are the best people!") are surprisingly not particularly high on the hell-spawned paladins 'people to be friendly with' list. Still you seem reliable enough and focused on getting the job done so we've got that in common. I can respect you even if I can't like you.