If you have any picnic things at home (plastic plates, glasses, bowls, mugs, cutlery), use those. Otherwise, I would just buy disposable paper ones in supermarket and a black sack for rubbish at this short notice on a first trip.
If you have a flask, bring that. Then if you DO only boil water in the microwave provided, you put it into the flask (or any leftover water into flask) to use later. Especially for later evening cup of tea/hot choc etc.
Definitely think easy for meals. Having a 1 ring gas stove would be really useful to be able to heat water for morning tea/coffee, cook a simple meal, make eggs or pancakes for breakfast, heat a tin of beans for hungry DC in late afternoon etc. A pot with a lid could do duty as a pot, kettle, or pan as needed - no need for loads of kit. And just bring a couple of implements from home - 1 sharp knife, 1 wooden spoon or spatula, 1 serving spoon, 1 small chopping board etc. (Knife will be needed even for cold meals to slice bread, slice salad items, open packets etc). A disposable BBQ could be a good idea for 1 evening meal, but have the food ready to cook as soon as the coals are ready as they won't last that long compared to a regular BBQ - but a great chance to have some fun with skewers, foil parcels of food, or cooking stuffed apples/bananas in skins with chocolate poked in/marshmallows on sticks for desert. (Pancakes for breakfast is something we do but mixing the dry ingredients at home and bringing in an (empty) plastic milk bottle with a screw lid, to just add the milk (and an egg) at the camp and shake vigorously to make the batter, which is then easily poured into the pan).
Definitely find the winter woolly hats and bring those to wear in bed, even if not outdoors as evening sets in. You lose most heat through your head and that's outside your sleeping bag/duvet set up. Also, a pair of clean, dry socks that are only used in bed are a GODSEND! (You will use more socks than you imagine generally).
Insulate yourself from the ground underneath as well as covering from air chill - so put a blanket under the sleeping mat or similar.
Some kind of footwear that is easy to put on during the night for midnight toilet trips. Flip flops (not great with socks), sliders, crocs, wellies etc.
Torch for each person. We use a 5l bottle of water with a headtorch turned inwards shining through the water as a lantern in the evening, which is a lovely soft but bright enough light.
Something a friend does when family camping is to give everyone a blue ikea bag for their clothes/belongings - easy for smallies to rummage through when they need something, everyone has their own things in theirs, easy to toss everything back into and relatively easy to stuff into nooks and crannies when packing up.