Quiche is my big-lunch stand by -- mostly because you can make them ahead and warm them just before serving.

Make a few different recipes -- including one with lower fat (search for "vegetable tart" recipes vs. quiche).

Goes great with salad and fruit. And honestly, warm up a cheese pizza for the kids.

Agree with PP above. I would do a platter for folks to make their own sandwiches.

Black bean soup in the slow cooker? Serve with corn bread.

If it is a lunch, why not a large cold cut platter so people can make their own sandwiches? We always use the small party rolls so people can just make a small sandwich.
You can do sides of pasta (maybe a mac and cheese for the kids), egg salad, potato salad, etc, and a fruit salad as well.

What about chicken salad with rolls/croissants (dieters can skip the bread), a green salad, and some easy sweet and sour meatballs in a crock pot (use frozen, serve in a sauce made of chili sauce and grape jelly). Maybe have some fruit and cheese as well. Hopefully the kids would like the meatballs (all kids I've ever served them to have liked them!) and the elderly woman would eat the chicken salad or at the very least have some green salad, fruit, and cheese.

I am hosting lunch this weekend for a group of 12 extended family members. The group includes 4 children with picky palates, two adults who are trying to diet and eat more healthy, one elderly woman who basically won't eat anything with any flavor (hates all sauces, herbs, spices....). I'd like to have something meets these requirements, still tastes good, and will not require too much time over the stove while my guests are here. Help!

I was thinking that a chili bar and a salad would be good, but I doubt that the elderly woman would touch it. Is there such a thing as a healthy casserole?

Any ideas appreciated!