Hi abc --
How fun -- a chance to be part of a special event and dress to the nines while doing so!
Sorry it's such a pain to find possibilities.
If you're ordering a second+ dress to try, I did want to put in a plug for the AP mesh sequin styles (looks like 1 and 3 would be the best in terms of what you want for neckline).
I wore one of them for a wedding and it was super-lightweight, packed like a dream (kept in plastic bag, rolled, shook out --> ready) and was so so SO fun to dance in as the bottom flares out when walking/moving. The sequins looked a little figure-skater-y to me in daylight when trying on eetc but shimmered in evening light.
[Suz had great suggestions for blinging out the dress Angie suggested. but I wore all the same type of stuff *with* my sequin dress. Magpie for the win. ;)]