LOL my memories of retro lunch is Appian Way pizza from a box or Chef Boyardee Ravioli
But like tallchick, I can see a nice fancy Crab/Shrimp Louie or other salad in my super cool retro green class blow glass bowl thingies.
I was looking at my Sunset Magazine, "The Dinner Party Cookbook" dated 1962. Not much to go with things like chili much less vegan, but lots of basic green salads. For their mole "Mexican Christmas Eve Party" menu they had a dessert of Baked Pineapple with Natillas (sort of a custard) where they baked/served in the pineapple shell for that bit of wow factor.
My first thought for fun and retro is fondue -- maybe chocolate fondue for dessert instead of a meat/oil or cheese version.
I also love to do a crowd size gelatin mold but a couple of problems, first not vegan, but after that you really need to make jello for 16 or so people to do it justice. I can't make a reasonable family size, only potluck and shower and neighborhood picnic sized.