I've got lots if experience catering for this sort of occasion and size (as a Mum not professional).
I would consider what sort of crockery and cutlery there is available.
If its paper plates I would rethink a couple of things personally.
A lot of the things you have suggested are great and the quantity size is easy enough to change.
I would consider some soft rolls for the children and babies. Some children prefer them in my experience.
If you are doing a cheese board, provide crackers. In my experience a cheese board with that many people is problematic and slows the buffet train down. Either do two or leave it out (I now just do cheddar and Brie).
If you don't want to provide cutlery just have slices of tomatoes and cucumber for people to put in a sandwich. Eating salad while standing or off your lap is hard work, so think about sitting arrangements. I typically have clementines, wedges of melon and grapes to provide some of everyone's five a day.
Less choice can also make it easier and help with quantities. I would do the Ham, Salmon and cheese and forget the beef altogether and if cost is your consideration (it is in my case) forgo the salmon for chicken drumsticks or a tuna pâté (I make a homemade one).
You probably have too much quiche, not everyone likes it and many people will only have one slice. Presuming you will get 12 slices out of a large quiche, I would do one veg and 2 bacon. I also would only offer one pork pie. I would do 60 small sausage rolls (at least) as kids tend to consume these at an alarming rate.
Individual rather than sharing crisps are also good as they help with portion control and again kids appreciate them.
I would also up the puds.
Not many people I know like the rich fruit cake so I do a big Victoria sponge celebration cake, fairy cakes/cupcakes and then a big tray bake or fridge cake as well as the fruit.
Things like this are always hard work but we as a family and extended family love them we do something on this scale at least once a year, with smaller ones (25-30) a couple of times.