OP here - thank you all! I forgot cheese!Will also include lettuce and salsa. I did not know you can buy bigger quantities of just chicken.
To the PP that asked, I ate the veg version of meat products but did not like them at all. Ofcourse my meat eating friends love it Yes I don't want to cook meat but will serve it.
These are all very helpful responses. Thank you all again.

Any special wraps or shells that I should buy?

My family and guests are all very easy going. As long as there is bellyful food, everyone will be happy.

Anonymous wrote:If budget allows, I’d just get 2 trays of meat from Chipotle. Steak and chicken are probably the most universally popular. It’s pre-cooked and cut so you’re done.

If you prefer to prepare it yourself, just get 3-5 lbs of ground meat (maybe 4-5 lbs if you have two teenage boys), and one envelope of dry taco seasoning mix per pound of meat. Follow the instructions, which generally will ask you to brown the meat in a skillet and then add the seasoning and a bit of water. Take care not to overcrowd the pan (best practice is to do about 1 lb at a time depending on the size of the pan) because otherwise the meat will steam and turn gray instead of browning properly. You can do this in advance and reheat the meat later if you want.

Also, if you’re doing ground beef, 90-10 (which refers to the fat content) is the best one to use. Leaner meat is likely to get dry and fattier beef is more likely to be greasy.

PP. Apologies, saw on closer read that you aren’t willing to cook meat! Then I’d definitely go with Chipotle. This will probably be considered a catering order, so you’ll have to call ahead of time.

If budget allows, I’d just get 2 trays of meat from Chipotle. Steak and chicken are probably the most universally popular. It’s pre-cooked and cut so you’re done.

If you prefer to prepare it yourself, just get 3-5 lbs of ground meat (maybe 4-5 lbs if you have two teenage boys), and one envelope of dry taco seasoning mix per pound of meat. Follow the instructions, which generally will ask you to brown the meat in a skillet and then add the seasoning and a bit of water. Take care not to overcrowd the pan (best practice is to do about 1 lb at a time depending on the size of the pan) because otherwise the meat will steam and turn gray instead of browning properly. You can do this in advance and reheat the meat later if you want.

Also, if you’re doing ground beef, 90-10 (which refers to the fat content) is the best one to use. Leaner meat is likely to get dry and fattier beef is more likely to be greasy.

Cubed sweet potato tossed with a chipotle seasoning and roasted/fried is a good addition to a taco bar. Can be a side or added to a vegetarian taco.

I often add cabbage slaw – very thinly sliced green and red cabbage, salt, pepper, olive oil, and red vinegar.

I also pickle very thinly sliced red onion. Put the sliced onion in a glass jar with a little white wine vinegar or lime juice, a little vegetable oil, salt and pepper. They’re delicious and look pretty.

You’re missing shredded lettuce and shredded cheese. I usually do chatter, but you can do a Mexican mix which is sold at the store.

I always have rice as well - that way people can make a rice and beans bowl, especially over salad. That will help fill up the teens.

I’d make pico de gallo (diced white onion, diced tomato, cilantro, salt, fresh lime juice)

I’d saute sliced peppers and onion in a little olive oil - add salt, pepper, and chile powder.

I don't see shredded cheese on your list which seems like a critical thing for tacos.

Tortilla chips to go with your guac/salsa and you could add queso if you want to.

Trader Joe's has several heat and eat options that could work (assuming you're ready to be eaten includes briefly microwaving) for meat options. They have a chicken fajita one I think. Aldi also has similar products including pork carnitas and chicken fajita. These are just meat and sauce, fully cooked. You just microwave for a few minutes and then serve. They're not amazing--but should be fine in tacos for people who want meat.

OP, I just want to say that it's okay, as a vegetarian, to serve a hearty vegetarian meal to your guests.

If you really want to serve meat, you can buy pre-cooked pre-cut chicken breasts at any grocery store. All you have to do is heat and serve. It's usually near the deli meat.

Where’s the cheese? If you’re not willing to sauté up ground beef, then use rotisserie chicken. Go to your local barbecue place and get shredded pork, chicken, and maybe some brisket. Don’t have them sauce it, bring the sauces home. Is there another function adult in your household who can sauce a couple pounds of ground beef with taco seasoning?

IMO, you don't need refried and black beans. Just do black.

+ salsa

Also - how about buying the meat already cooked from Chipotle?!

Will you cook with plant-based meat like Beyond or Impossible, or use frozen "meat" crumbles? Most meat eaters will be fine with it, especially mixed with other ingredients.

Whole Foods sells chicken breasts in the prepared area that are ready to go.

1. Sauces- add SALSA! Mild will please the most palates.

2. You should fry onions and peppers in fajita seasoning. raw=gross except for the tomatoes. Add a small bowl of shredded lettuce too.

3. For meat, I think you can get shredded chicken right in the cold case or look around at the deli. Ground beef could be a little trickier. But supermarkets have amazing prepared food. So even if the chicken is "lemon chicken" prepared, you can still throw taco or fajita seasoning on it and call it a day. If you don't really want to deal with much meat, chicken is a great option. You can also look for shredded pulled pork since that's another meat that tends to be all completely ready for you. Again, don't worry too much if it's flavored. It will be fine.

Don't forget shells and wraps.
Your sides look fine.
Good luck. You sound very considerate.

Total 7 people, of which two are teen boys who will basically clean out the house! A couple are vegetarians. Me being one of them, I am clueless about meat and hence this post. I can buy the meat but it has to be ready to eat w/o need any prep. I have never done this before so it would help if you can suggest brands/stores where I can buy. I looked up the taco bar results in this forum but didn't find any that needed extensive help like me.

Questions:
What sauce if any? Or is guacamole and sour cream enough?
Any spices to keep on hand?
What meat to buy and where to buy that is ready to serve?
Should I fry the veggies? If so, with what spices?
What other substantial sides can I offer? I have cookies and cake which will take care of desserts.
I don't mind cooking and baking as long as it is veg. If it is meat, it has to be ready to be eaten and needs to come from a store.

Here is what I am thinking so far:
Tortillas
Guacamole
Lime wedges
Peppers
Tomatoes diced
Onions diced
Black beans
Re-fried beans
Sour cream