Talk to your DM
Ultimately, your DM is the one designing encounters, so he/she needs to know that you're playing a non-combat focused character. Your DM can ease back on the encounters if necessary and provide options for your character to do what he does best out of combat. You should also find out if the type of campaign your DM is running is appropriate for this type of character. We can postulate about the possibilities of your party all day, but it's meaningless without knowledge of your DM and your campaign. This doesn't mean "tell us about your campaign", this means "talk to your DM". Ask your DM this same question, and that will be a better answer than any we can give.
Either way, I'll take a crack at answering your question, but the number 1 thing you need to do is talk to your DM about this.
So, is it fair to the other players to make a non-combat character
that cant help much in fighting in a campaign with a fair amount of
combat?
Absolutely, but...
You should get on the same page with your group. Your character is one that excels at the out of combat stuff, so you need to make sure they're on board with you being a stand-out character when not fighting and a behind-the-scenes character when you are fighting. Your character is also one that can prevent combat from happening if you so desire, so you should find out if your group wants to do that ever.
Speculation about your group
Looking at your group, you've got 2 bards, 1 rogue, and 1 rogue/cleric (you). Your group is not suited for brawling very much, like a group with fighters, barbarians, and/or paladins would be. Bards are good support that can deal out some ranged damage if they choose to build that way and rogues are good at dealing damage to distracted or unaware targets. So if you're playing a non-combat character, you may run into trouble.
What does this mean?
Your party needs to play to their strengths. You can be a valuable asset as a support, someone that heals, controls enemies, and helps friendlies. You are likely not good at damage, so the rest of your party should be, or it may not work. Having only 1 melee with 3 supports (2 bards and you) might not work well against heavy hitting targets. Your party's strength lies in avoiding combat and surprising targets when combat is necessary and controlling targets to make them less scary. If you focus on doing that, you should be alright. Grab spells that help your group and use your sneak attack when its available (you can do this at range too), because it's a pretty good chunk of damage no matter who you are. A diplomat can still carry a big stick.
Again, talk to your DM and find out if this is feasible.