Well, for stats, you're going to want str and a decent bit of con. You can go with 8 dex, but that hurts your dex saves, athletics rolls (so you don't get pushed around), and initiative, so that isn't ideal. You can avoid the need for int by mostly focusing on things that buff you, rather than require to hit rolls on enemies and/or them to fail saves. Wisdom saves are also important, because of spells like hold person. And to try and fit charisma on top of that... That said, what options you have in conversation will be based on things like class, background, race, and so on. The stats matter for if you succeed
You could go with something like 14 str (with +2 making it 16), 10 dex, 13 con (and the +1, making it 14), 12 int, 10 wis, 10 cha, and that leaves you two points left to play with. You could use that to up dex, wis, or cha to 12, for the extra +1 on rolls, or to push str up to 15 (depending on what feats you have planned that add to str, and/or certain other in game things).
I'd probably go fighter to 5 for the extra attack. Then for the next 3 levels, 2 wiz, 1 fighter, or 1f,w2, depending on if you want to get the wizzy subclass in first or another feat. After that, maybe another level of wizzy, as that'll give you a spellcaster level of 5, meaning you get 2 casts of haste per day, if that's your goal. And then however you want to get to your final class mix.
As far as feats, there a few that would aid with conversation, like ones that gives you some more skills. Also a few that give access to some spells, but with you being a wizzy, you'll already have access to most of those spells. And for a bunch of those you don't, there are items that let you cast them available in level 1. So you'll probably be more combat focused. Like, if you intend to haste yourself, you'll probably want War Caster. And there are the various ones that provide a useful benefit plus +1 to a stat. Or maybe you'd be after Alert, to give you a +5 on initiative, to make up for your lower dex. But if you do want to portray your guy as being a bit more charming/witty, then maybe Skilled for 3 extra skill profs? Or else Actor, for +1 cha and double prof bonus for deception and performance (and will give you prof in those skills if you don't have them yet).
You can find a nice list of feats on a couple of the wikis, so just look through them. From the fighter class, you'll get feats at 4, 6, and 8 (and 12, but you're MC'ing, so that's out). And wizzy, like most classes, is 4, 8, 12. So if you plan to go 8/4, you'll have 4 feats to pick. And if you are thinking 10/2 or 9/3, you'll have 3.
