3 fighters, i cleric, 1 wizard, 1 sorcerer?
And, a question, sorcerers use chrisma instead of Intl?

That depends on which game you're playing (you failed to mention that in the OP; IWD:EE and IWD2 are different games with huge differences in the gameplay mechanics.

(Assuming you're not playing classic IWD1 because of the sorcerer)

The sorcerer is also in the Enhanced Edition, but neither the manual, nor the game mention what the primary stat is. That build looks pretty good. I recommend having one or two of your fighters as ranged. Doesn't have to be a dedicated ranged character. Sometimes I like to make fighters who can switch between melee and ranged.

Edit: you should replace one fighter with a thief. You'll need to search for traps in dungeons.

I did mention that. IWD: EE Sorcerers are like Baldur's Gate 2 Sorcerers; they don't need any stat, though there is a minimum Intelligence requirement for using scrolls. With that said, scrolls are too scarce to use that way; you are going to need most of the scrolls you find for your wizard.

In IWD2, Sorcerers do need Charaisma. You will want at least 19 Charisma if you want to be able to use level 9 spells, so be sure to start with at least 15 (so you can reach 19 at level 16); you might wish to start with more for extra spells and save DCs.

Bards are useful in both games, especially since some of the bard songs are quite useful in these games (I recommend turning off the party AI if you are going to use these songs). In IWD1, they level up faster than mages, making them great choices for spells that scale with level. In IWD2, they learn spell like a sorcerer (but with a different spell list, including minor healing magic), so they don't compete with wizards for scrolls.

Again, it really does matter which game you are playing.

If you're talking about IWD:EE don't play at insane difficulty, the bonus XP will make the game easier than normal, if you want a challenge disable max HP at level up and don't raise dex and con so high at creation that they grant HP or AC bonuses.

I'd consider making the wizard a specialist since the sorcerer can pick the spells from the forbidden school.