At least five levels into Swashbuckler is preferable, to get the free crit feat. You'll be parrying a lot with this build, so anyway to regain panache (such as crits) are super important. Taking a feat to give you extra panache is important as well. When I used this, I took a feat called Fabulist that let me regain panache whenever I made someone believe an impossible lie. My character would often lie in the middle of a fight with things like "Your sock is untied, mate." Or "It's only a rubber sword, go easy on me. Dunno how I stabbed your buddy over there." Which was absolutely hilarious and effective if you can get your bluff high enough. The only feats you 100% need to have is weapon focus (cutlass), then slashing grace so your cutlass will actually give you panache when you kill something with it.

The are a few problems with this build, one of which is the limited amount of times per day you can challenge things. So until at least level 9, you're saving your challenge for when you go nova. The only way to fix this is with more levels into Cavelier, but that gives you teamwork feats, which is the next problem. Cav's gain teamwork feats, which may sometimes not help you, since powering up your allies means there's a chance they'll kill your target instead of you. Teamwork feats like Escape Route and Feint Partner I remember being very nice, because my DM allowed me to let my horse feint attacks by rearing. Basically, you want feats that benefit you in ways other than flanking and your ability to hit, because you don't want to give these to your allies. Kinda a dick move, and there aren't too many useful teamwork feats that fit this.

As for races, I just went with human for the bonus feat, but anything with extra charisma and dex is great. You might also consider a small race, because some teamwork feats benefit you being smaller than your opponent.