ok so background I'm a relatively new DM that is starting up my first longer running campaign (I've done a couple of smaller one to two shot session but never anything longer), with the campaign we're going to be running the wildmount setting and the extra stuff from the sourcebook, each of my players rolled their characters in private with me and told me their character concepts, this is where the problem potentially came up, out of my 5 players 2 immediately decided they wanted to be grinners as their background and begun leaning heavily into that for their character concept, and two more decided they wanted to be volstrucker and leaned heavily into that to create their characters, and the both want to still be working as volstruckers, so what I've got is a party where one half of the party is the polar opposite of the other half, I have a couple revolutionaries and then a couple people who want to be the boot of the man.

here's where I get to the meat of the issue the only way I can see to make this work without making practically half my party rework their backstories and the characters they've worked to create is to tell the volstrucker players that they've been given the mission to infiltrate the grinners, my question is, is this fair to my two grinner players? and if so should I tell them out of character what is going on, so that they know that some people in the party are potentially working against their long term character goals? or should I not let them in on it unless they're able to work it out in character?

yeah we've now gone over some stuff in general terms as a group, the players all out of character decided how they met up and why they've decided to travel together, I allowed the volstrucker characters to keep their secrets to a degree but not really at the same time, as the grinner players know what that their backgrounds are, and that this may cause their long term goals to clash, just not the specifics of it or that they're still in the volstruckers, they were all just excited for the potential character drama and didn't want any spoilers so I left it there, I did like though that they immediately formed off into planning out two little individual buddy cop dynamics , and my volstrucker players decided they'd go with a torn loyalties character dynamic with their characters caught between their loyalty to the empire and their loyalty to their new family, the grinners wanted their inciting incident to be that the other members of their cell had suddenly started disappearing one by one,  which allowed me to make that the same inciting incident for my volstrucker players by making them at least partially responsible for it,

I think it's good that you handled this with OOC discussions and that all the players have talked about it as players and decided together what they want out of the campaign. Since they all want the character drama and goal clashing, when this happens in game, it should not cause any player drama. This is the way to handle things, by having player to player discussions. Yes there may be a little bit of spoilers but it is so much better to do it that way than to try to keep everything secret and then have the clash be between players instead of characters.

Good job making this work out. Keep up the player communication as much as you can especially when the character drama ramps up. If they get really into it, it may be hard for them to separate character from player so make sure you keep an eye on this and maintain play-group cohesion. 

But it sounds like you guys are on the right track and the potential character RP looks really interesting. Should be fun.