They are fab suggestions.
What about stuffed tomatoes even if you made cooked once I bet they would be nice cooled down, now I have said that I like that idea with some cold quiche.
Devilled eggs as a snack, part lunch? I do like pasta with a tomato bolognese sauce cold, is that weird? I really can't think of much more to add that is 'cold' meal ideas but something of hot and cold is baked potato and tuna? I am interested if anyone else has any ideas