The answers to some of your questions are dependent on the temple itself. How many monastics are in residence? And will other laity be offering food, or is it just yourself? What is the ethnicity/ national origin of the monastics?
Somewhere on Dhammawheel is an thread/ article about how monastics in Thailand are at a higher risk for diabetes and other health problems because the laity tend to serve food high in sweets. Monastics at vegetarian temples might be protein deficient. When I offer Dana meal, I use organic ingredients, & cook from scratch. (Usually I make a casserole, because I can make it ahead of time, transport it, and reheat.) I always bring a green salad. I am vegetarian myself, and gluten free, so I try to provide a veggie protein. However, one time I brought a pizza. The Angarika grinned ear to ear, and assured pizza was fine. I have witnessed other people serving meals as simple as granola and yogurt, and as complicated as a Thai 5-course meal. Often I see other people attend to details like dessert, coffee, etc.
I do serve soups and stews. I offer this in pre-served bowls, and present this on a seperate tray. This practice allowable at the temple where I go, not sure if that is universal.
One time I offered tacos with a full taco bar. I had to offer each food/ condiment item, separately, and it was quite time consuming. I would do it again, be remember "the devil is in the details."
"As I am, so are others;
as others are, so am I."
Having thus identified self and others,
harm no one nor have them harmed.
Sutta Nipāta 3.710