Black one-shouldered draped sleeveless cocktail dress from Calvin Klein ($49.99 - I actually just recommended this to a friend for a wedding this summer, she ordered it and likes it a lot.  It so classy and sleek but could totally be glitzed up with red shoes or metallic jewelry.  I'm a big fan and am thinking about getting it myself, the price is certainly right.)
Petite Seamed Detail Sweetheart Body-Conscious Dress from ASOS ($64.49 - lovely classic shape and I assume at your height you can wear petite sizes - only issue is, based on the picture, it looks like you'll need to get a slip under it.)
Calvin Klein Strapless Neon-Trim Dress at Dillard's ($59.40 - another fairly simple yet classy number from CK - though the neon pink adds a twist.  Its a cotton/spandex blend, meaning it should breath well in the heat, and you could maybe add interest with a pink wrap.  Overall pretty cute - though not sure if Dillard's will ship to you - might have to find it elsewhere!)

Suzi Chin for Maggy Boutique Ruched Matte Jersey Dress at Nordstroms ($118.00 - the Suzi Chin line has lots of great dresses for this sort of thing but this is one of my favorites.  56 reviews and it has 4 stars and I just think it looks really flowy and flattering - maybe consider one of the non-black colors...I know, scandalous, but the purple is cute!)
Nue by Shani pink and navy two tone cocktail dress from eDressMe ($92.00 - so this is kind of a curveball both because its final sale and because its not really what you described but something about it just called to me, plus eDressMe ships world wide so that's a plus.  Only available in a size 6, so may run too big, but sometimes these sorts of dresses run kind of small, so it may even out in the end.)
Paper Dolls Mirrored Lace Body-Conscious Dress at ASOS ($98.43 - another color option, I love cobalt and black and think its both super on trend right now but also classic.  ASOS ships internationally I believe and I think this dress is fabulous.)

Corso Como Dover Pump at DSW ($109.95 - I feel like red pumps are a great combo with black dresses and the cut-outs at the back of these give them a little interest.  I don't know, they're cool.)
Ivanka Trump Ariell High Heel Ankle Strap Pumps at Bloomingdales ($105.00 - metallics are my other favorite with black dresses and I'm super into gold right now, so here you go.  I also really like black and gold together, like these ones at Piperlime, but they're only available in limited sizes so I went with the Ivankas instead.)

ML Monique Lhullier Black Knit One Shoulder Sequined Side Ruched Dress at Bluefly ($115.97 - a comfortable fabric but the ruching, sequins, and asymmetrical strap adds interest.)
Tadashi Shoji Portrait Collar Pleated Mesh Gown ($298 - I LOVE this one - someone in my life should have a formal event so I can purchase it please.)
Adrianna Pappell Illusion Yoke Pleated Dress at Nordstroms ($158.00 - extremely well reviewed and looks very flattering - a bit prim and proper but lovely.)

Adrianna Pappell Pleat Bodice Rossette Ballgown at Nordstroms ($238 - fun if you want to go true ballgown.)
Starlight Hearted Dress at ModCloth ($202.99 - loyal readers of the site will recognize this dress as I've posted it before and still love it - may not be long enough but the poofy skirt and gold accents might make it work, especially if paired with awesome metallic gold shoes and fabulous jewelry.)
JS Boutique Cap-Sleeve Beaded Pleated Evening Gown at Macy's ($136 - yay navy, yay sparkles.) 

Tadashi Shoji Asymmetrical Ruched Mesh Dress at Nordstroms ($228 - I love Tadashi Shoji, I think they make some of the most interesting clothes out there, and I like the design of this one.  Flattering and interesting all in one.)
Lauren Ralph Lauren Illusion Yoke Matte Jersey Gown at Nordstroms ($180 - a sleek simple long option with a nice price point to boot.)
Adrianna Pappell Lace Fit and Flare at Nordstroms ($178 - I love the see through detailing at the bottom.)

Adrianna Pappell Short Sleeve Sequin Mesh Gown ($278 - SPARKLES - this row is having non-black dresses because I'm stubborn and because of reasons.)
Colorblocked Blanche Dress at Kate Spade New York ($249 - a little whimsical but styled right it'd be great.)
Dalia MacPhee Strapless Pleated Ruffle Chiffon Gown ($298 - another repeat but that's because I'm in love with it.  The color and shape are gorgeous - though reviews say it runs large.)

Okay - the shoes here really depend on what you buy - but you could wear either of the shoes from above again with most of these.  Now - I know you said you had the brunch on lockdown (and I'm sure you do) but I came across a few casual dresses that would be great for it, so I thought I'd pass them along.

Adrianna Pappell Embellished Jacquard Sheath Dress at Nordstroms ($138)
Colorblocked Ribbon Waist Sleeveless Dress at Ann Taylor Loft ($69.50)Petite Sleeveless Seamed Ponte Dress with Pockets at Land's End ($69 - want this one badly for myself.)

All of these would look great with a nude sandal or wedge pump and a white, beige, or contrasting color blazer or sweater.  Okay!  Hope this post helps.  Let me know what you end up buying - I'm sure you'll look glorious no matter what you choose.  Happy shopping and may the odds be ever in your favor.  Readers - do you have any recommendations for Reader LK?  Do you agree that NYC wedding means a black dress?  What colors do you like to wear to weddings?  Leave your thoughts in the comments!

EDITOR'S NOTE:  Have you entered our promotional contest yet?  Why not?  You should really do that now.  Like now.  Yes now.  GO DO IT.  (Okay - done now.)

I'll answer your first question first - I think its probably fine for a wedding.  On the website it is described as "sky-blue" and it looks fairly blue here, so I think on the color you're probably safe.  In terms of appropriateness otherwise, I think its lovely - though its maybe hinging a tiny bit on the dowdy side (I wish there was another color there.)  I would definitely want to punch it up with some fun accessories and shoes to add a little bit of color and maybe even sparkle to it - but overall I think its a nice look.  So first, let me offer up some shoe possibilities and a couple of jewelry options - then I will move on to a few other similar scallop dresses for your consideration.

Enzo Aglioni Maiven Shoes at Macy's ($49.99 - I like the idea of a textured metallic - gives a little shine to the outfit while still being classic and not too crazy.)
Pour La Victoire Case Mary-Jane Pump in Teal ($39.99-$249.99 - I think a mary-jane or a t-strap pump would be a great way to reference the era of the dress without being too literal.)
Vince Camuto Lexis Pump at Designs by Stephene ($49.99 - these might be a little too high for you - and I'm not sure how you feel about the studded look - but I love the idea of a bright cobalt or navy shoe - I think a second shade of blue with this look would be awesome.)
(If you like any of these specifically but want a different, similar recommendation, let me know.)

Inlaid Hexagon Cuff at Lori's of Chicago ($36.95 - I like the idea of adding some color in a bracelet - either coordinated with the shoes or in a contrasting but still friendly color - purple would be another nice option.)
Tortoise Box Bead Necklace from Forever 21 ($9.80 - check out all their options - they have amazing sales now.)
Lacquered Twist Necklace in green and gold from Forever 21 ($6.80)

As far sa other dresses - I didn't see much that I thought was particularly good in your aesthetic and in your price range.  Readers, have you seen any similar dresses that you particularly like?  And KG if you decide not to go with this dress, come on back and I'm sure I can find you something else.  Hope these ideas help - and have fun at the wedding!

Lauren by Ralph Lauren Print Fit and Flare Dress at Nordstroms ($149 - this would look lovely on an x-shape - maybe better for the rehearsal dinner because of the white in the print?  But given the other colors, I'm sure it would be fine for either - but I'm fairly non-traditional when it comes to wedding guest wear.)
Lauren by Ralph Lauren Knotted Jersey A-Line Dress at Nordstroms ($130 - I love this color and it would pair great with gold and turquoise jersely - seriously - beautiful gold sandals and turquoise jewelry [like this maybe] would look amazing.  Probably for the rehearsal dinner but would also work for the wedding - depending how nice the jersey is.)
Donna Rico Print Cotton Fit and Flare Dress ($88 - I like this pattern - and the price is right.)

Ksenia Printed A-Line Dress by BCBG ($298 - a little pricey but I love the pleated look and the colors are fresh.)
Eliza J. Dress, One Shoulder Beaded Satin Cocktail Dress at Macy's ($168 - satin is taste specific but this is pretty.)
Feather after Dress at Modcloth ($89.99 - pretty print - but reviews say to order a size up.)

Cynthia Steffe Lida Color Block Crepe Dress at Bloomingdale's ($148.50 - a sheath with little something different).
Haute Hippie Sequin Asymmetric Drape Dress at Shopbop ($238.50 - this is different than most sequin dresses - I like it.)
Summer Bouquet Sundress at White House Black Market ($160 - I have a very similar dress to this from WHBM and I love it - beautiful shape and nicely constructed.  Great for weddings, fun to twirl in.)

So!  Hope these ideas help.  Let me know if they don't work and hope they expand your idea range.  And a reminder - if you decide to buy any of these - click the link and buy them through here.  That would be awesomesauce!!