Hey Drew. I laughed out loud at your question. Lunch at Galatoire's poses its own kind of risk... and the people-watching is just as great as the food! Which kinda proves your point here. I get it. Between growing up in Mississippi and immediately fleeing to New York afterwards, I got a lot of practice when it comes to wearing stereotypically southern stuff my own way. There was a lot of trial and error through the years. What it really boils down to: one (southern) lead singer at a time. In other words, break up your southern staples.
So, for instance. A seersucker jacket paired with jeans has a casual, knockaround quality, while a pair of pants becomes the star when paired with a white oxford or a navy polo. White bucks can punch up khakis and a sport shirt, and give ya a reason to look down. And unexpected muted colored suits, like tan poplin or navy seersucker can be stylish for the southern heat without necessarily looking capital-S-Southern. (That tonal navy one in particular is like secret seersucker.) But let's break it down by the items you listed.
First, you don't want to do the white bucks WITH the seersucker, or even the poplin suit. It's a little too on the nose. And, particularly if you live someplace that isn't the South, you run the risk of looking like Central Casting. There are some guys who can carry this off (usually the ones who hang out at Galatoire's), but the fact that you're asking already tells me it may not be for you.
But, okay, what do you wear white bucks with if not a suit? I think those look best with a pair of jeans or khakis, and a toned-down sport coat. Sometimes I'll add a seersucker jacket, maybe, but most of the time I'm wearing them in place of any other bluchers. The most important thing is to get a little dirt on them.
As for the suit... whether it's poplin or seersucker, the easiest way to tone it down is with your shoes. That takes it from costumey to cool. Last week I wore my khaki poplin suit with slightly scuffed-up desert boots, which felt more Lawrence of Arabia than anything else. Out of the two, poplin tends to be easier than seersucker, especially because these are traditionally in light, muted colors.
navy-on-navy - the "secret seersucker"
I think the stripe on a seersucker is a little more intimidating, although it shouldn't be! To be honest, pulling off a seersucker suit is mostly in the attitude. You want something – anything – that feels a little 'you.' Maybe it's an interesting pocket square instead of plain white, or possibly a knit tie instead of the club tie you'd expect. Come to think of it, SKIPPING the tie is an easy way to tone it down, too. A suit (in any fabric) without a tie makes the whole vibe less precious... like you're truly comfortable in it. Polo shirt, no tie, tie, open collar... it's all fair game with seersucker. And as far as shoes go, there aren't a lot of rules there, either. Last week I wore a seersucker jacket with a white shirt, grey high-twist trousers, and sharkskin tassel loafers... no socks. I also think it looks cool with sneakers, whole-cut or low-top. And Ann dug up the old picture above where I'm wearing a seersucker suit with black Chelsea boots and a black tie, both of which by definition help to add some rock 'n' roll.
That suit in that Polaroid was actually the first-ever suit I had made for myself... silk seersucker, made by Nino Corvato in New York. The stripe was red, with a tea-dyed color in the ground instead of white, so it looked a little old to begin with, and it had pearl buttons. Today, I would probably counsel a 24-year-old against something like that for his first suit, but, hey, you don't know what you don't know – and I definitely didn't. But I wore that thing everywhere. It nearly landed me in a fight at the Back Door Tavern in Knoxville, when we showed up after my sister-in-law's wedding. By midnight, most people there were probably ready for a fight anyway... but that red seersucker was not well received. I stepped down from the challenge, but the lesson here may be that if you're going to wear a seersucker suit in East Tennessee, you gotta be ready to fight for it.
I apologize that my answer to you seems so stupidly simple. Shoes and attitude, or when in doubt split 'em up. That's all! But it really doesn't have to be that hard. The thing about these fabrics is that they're "stereotypically southern" for a reason... as far as tailored clothing goes, there's nothing better in the heat. A seersucker jacket is way too practical to relegate to the back of your closet because you're afraid of looking like you're in costume. You know, I just learned that the most-entered search term on our website is 'seersucker' – that's most searched of all time, or at least since we launched in 2011! That tells me that you're not the only one trying to figure this out. I really do think every man can wear it – maybe not a whole seersucker suit, per se, but definitely one piece at a time. Maybe next time I'm at the Back Door Tavern I'll just do the jacket with jeans.