As long as there is plenty of food available, I'd say that a tea of sandwiches or salad or similar (slices of quiche, cold chicken legs, cold sliced meat, fritata (or whatever that spanish omlette is called) etc) would be fine.
Or perhaps dinners that can be cooked ahead so you only have to serve - lasagne, sheperd's pie, fish pie, chicken and mushroom pie etc. Or even the occasional chicken nuggest/fish fingers/battered fish/chicken kievs and oven chips/potato wedges - of which you can have the less healthy freezer aisle option or the more healthy homemade option depending on your time available earlier in the day.
I only got to the end of p.1 so far, but if the issue is the washing up etc, could you have the prep work done and cleared before they all get in, and leave dinner plates stacked neatly out of sight in a washing bowl (or a dishwasher if you have one) until MUCH later when ALL dc's are in bed?
Or perhaps clear prep dishes out of sight (have you space to designate a cupboard so your DD doesn't SEE it, so it's not an issue for her?), and use paper plates that then get binned for the meal.