I would do the same but 'size' up to the numbers you have. Maybe add some salad, smoked salmon to extend what you already plan. Keep it light but flexible so people don't feel obligated to eat or can pile up as they want.
We normally have a large pork pie in addition to the cheese and biscuits. I don't like it but it gets demolished. I make a huge batch of sausage rolls on Christmas Eve too, which children enjoy more than anything else on all the picky buffet type teas we have over Christmas.
What you've already listed, I agree that salad and some other picky protein bits like sausage rolls, pork pie, cocktail sausages are good. Nobody expects anything too fancy do they? Personally I love the cold cuts with a bit of mayonnaise or chutney, I usually boil and glaze a ham on Xmas eve so we have this and the turkey leftovers to eat cold for Xmas day tea. Mmmmmm.