Well, most people go to church on Wednesday evenings so your plan wouldn't work for most. I assume you've taken religion into your change of plans....
Tacos can be taco salad, taco burgers, cheese tortillas, soft tacos, crunchy tacos, etc....we love taco night because everyone eats something different that they like. My girl will put Colby cheese on her flour tortilla and warm them in the microwave for 22 seconds and have yummy cheese tortillas. Then eat a few spoons of taco meat on shredded lettuce. I've also used taco flavored TVP from Emergency Essentials so it's basically a non-meat meal. Some like meat and cheese on a flour tortilla and some like to take a warm corn tortilla then spread some butter on it then pile on the refried beans, meat, and cheese on top of it. Taco night is usually a hit with everyone.
I think you are overthinking this. Let them know what you're having and they can bring something for that 2 year old if they don't think they'll eat what you're serving.
Think of things that restaurants have that we seldom take time to prepare.
Meatloaf, homemade mashed potatoes, white gravy, corn or green beans and warm rolls.
Turkey and dressing, sweet potatoes, green bean casserole, and maybe a salad.
Chef salads where everyone puts their own ingredients on. Everyone can bring some too.
Taco night. Do it more open where other things can be done with the foods offered.
Italian night, chicken Parmesan. Flatten out, roll in Italian seasoned bread crumbs, fry it, keep it warm in the over. Make a homemade marinara sauce, cook some pasta. On the table you put it all out and everyone puts the pasta, chicken, sauce, top it with a slice of Mozzarella cheese, then add a side and wonderful garlic butter Parmesan rolls. Do a Chianti pasta or a pizza casserole or something like that this is yummy and kid friendly.
One of our favorites is Lion House Sweet and Sour Meatballs. I make a double batch of Oven Steamed Rice. If I want to do a side with this I pick something without a strong flavor. The sweet and sour flavor needs to stand alone so you can savor it.
When making the Lion House Sweet and Sour Meatballs one thing...you need to double the sauce recipe. Make the meatballs smaller rather than larger so the sauce flavor will permeate them more. Use a good BBQ sauce that doesn't have a weird tang to it. I use Head Country regular and it's okay. I don't use that sauce for any other BBQ foods though. I don't really like it, I use their Smoke flavor when I'm eating BBQ.
Speaking of BBQ, do burgers and hot dogs on the grill. You can do the fresh veggies on it too.
Baked potato bar. They can bring their favorite topping if they want. I like to buy some Jim Beam Pulled Pork from the Meat section at Walmart and top my baked potatoes with that. I also like to do a good chili on one occasionally. Not much into broccoli and cheese on it though.
There are many meals you can come up with if you just think about what's on menus from your favorite restaurants. That's where I come up with a lot of new ideas.