Biscuits could be good for part of the breakfast too, especially with some cheap jelly or jam. And if either of you can make sausage gravy, that would be a cheaper alternative than cooking that much sausage or bacon for them! (One of the sausage brands sells good sausage gravy in little refrigerated pouches, over by the sausage in the store. They're frequently on sale 10/$10 here, and you could look for a coupon for $ off any product of that brand.)
Potatoes can be a really good side dish/meal stretcher morning, noon, or night...
**There are still some Betty Crocker and Hungry Jack instant potatoes coupons out right now, and I've seen those on sale a lot lately. The BC Yukon Gold are very good for mashed potatoes, and the au gratin or julienne potatoes could be jazzed up with peppers, onions, ground beef, taco seasoning, etc-- tons of possibilities with add-ins!
**I don't know what kind of time constraints you'll have, but whole potatoes are also great low-cost fillers. Thin sliced for fried or au gratin; shredded for hashbrowns; chopped for potato salad or adding to soup or stew; wedged and sprinkled with seasonings for potato wedges; or of course, mashed with evaporated milk, margarine, and salt! You could also do a baked potato bar and offer enough toppings that the potato and toppings become the whole meal (I do that often myself!)...
One other tip: when I make soup or stew for a large group, I try to make it a little thinner than normal. It helps stretch it further, plus keeps it from getting too thick while trying to keep it warm for everybody. (I've also secretly stretched lemonade, kool-aid, and tea by adding about 1/3 to 1/2 more water than originally called for. But be careful with this one-- add water slowly and test-taste along the way, as some brands are
much stronger than others!)
HTH! And thank you to you, your hubby, and your church for providing a safe, fun, learning environment for these kids!