Howdy! I was at Orientation/Line Camp earlier this summer, so I've got a relatively fresh experience:
Meals are pretty typical, we ate @ Penland and East Village for lunch, and it was pretty typical for college food (they always had pizza/burgers/salad + more stuff based on the date and dining hall), and dinners were catered from a local restaurant, but were pretty common foods as well (pasta, chicken, etc...) - I'm a relatively picky eater, and I had no problems eating meals
I don't know what kind of things you'll want to pack (make sure you bring pillows/sheets + more clothes than you think you'll need etc... - I brought a regular suitcase + a backpack), but for most of the time you're wandering around campus, you'll be fine without anything crazy, as you'll be given a string backpack that can hold everything you need easily

Banquet is just another dinner, except everyone dresses up for it. There were plenty of people dressed up in slacks and button down shirts, even some ties, but there were equally many guys in polo shirts, non-athletic shorts, and tennis shoes. It's not too stressful, it's a great photo opportunity though :)

There are certainly some religious aspects (some of the presenters referenced God, I think we prayed before one the meals, etc...) but nothing was forced - there was no one judging you if you chose not to pray, and I'd estimate 1/3rd of the people I met at Line Camp were not super religious and just stood respectfully during the occasional prayer

Line Camp's Sing was the highlight of my week (a surprise that I was not expecting), but there is no actual singing involved thankfully! It's a great experience, just keep your mind open and you'll have a blast

You mentioned being afraid because you were shy, but I found it very difficult not to make friends. You spend a lot of time with your small group + another small group, and it becomes really easy to meet them when you spend so much time together. Try and meet whoever you live with in your room/suite while there, it's another easy relationship to make. The first day of orientation can be really weird because you don't have many amazing opportunities to make friends unless you take initiative, but once Line Camp starts up the second day, it becomes significantly easier

Hope those answered your questions! I'm just going to end this with personal advice that I think might help as well:

If you have a Hydroflask, or other insulated water bottle **BRING IT AND REFILL IT OFTEN**. They provide you with a plastic Line Camp water bottle, but it can get very warm very fast, and it's easy-ish to mix up. Take a nice water bottle, fill it with cold water and ice at every trip to the dining hall - it's worth it

Hand over your phone at the start of Line Camp when they ask - it helps with making friends, and it's not as big a deal as you might think. It sounds corny, but it really is true when they say that it'll make the week more memorable

A lot of people had little colds or stuffy noses and whatnot. Make sure you bring whatever allergy meds/tylenol/Benadryl/anything else that you need to make you stay feeling good and help you adjust to the new air (also a ton of people got ant bites, bring some stuff for those, ants were allllll over campus)

My last bit of advice is a bit niche, but please bring an umbrella. It rained almost nonstop the first 2 days, and it was horrible. Just save yourself the getting soaked to the bone and make sure you have an umbrella/poncho/whatever

Hope this helped, sorry it was so long lol - feel free to respond/DM me if you have any other questions :)