Don't know how old the children are, this estimate assumes elementary school or younger.

Count this group as 1/2 of 100. This is what I would do:

2 gallons chicken salad plus about 4 pounds bread or 4 dozen sandwich rolls
40 hot dogs and rolls
garnished for the hot dogs- see the sandwich page, do 1/3 of 100.

I would switch the fettucine to rotini or bow ties, much easier for kids and picnickers to eat, about 3 pounds dry noodles plus add ins.

I would definitely do fruit trays- 1/2 the deluxe tray for 100 would be about right, see the fruit tray page.