Two of mine are really fussy. One won't eat sandwiches at all. He's very particular about how food feels and look and gets stressed by marks on apples for instance, so that can be difficult too.
Their lunches look fairly similar to yours. One will have a yogurt, an apple, dairylea dunkers, some popcorn and mini cookies and a carton of orange. It's hit and miss if it gets eaten though. For a while pepperami, mini cheese and some chicken pieces were in favour. He's since decided he will only eat these at home.
The other one likes fruit and veg fortunately so apples, oranges, carrots, grapes or raisins and mini toms. An occasional sausage roll. A yog and a cake bar/choc biscuit. With a carton of fruit juice. The only sandwich he will eat is chocolate spread which is frowned on at school but I have been known to put one in occasionally.
When they first swapped to sandwiches I found it really stressful because they kept going off things and I was worried the school would think what I was giving them wasn't enough but I actually think they are eating more now that when they were having school dinners. I'd found out one wasn't eating anything at all on certain days and the other one would only have a dry cheese baguette (which weirdly he won't eat at home).
Thankfully my other two are not as fussy. I must admit I love Friday's though because it's pizza day at school and they are all happy to have a school dinner that day so I don't have to stress!