I understand what you’re asking here.
SWISS serves a lot of cheese, so if you’re not good with cheese then order a special meal. If you only have a small problem, I suspect you’re ok with hard cheese so you could be fine.
I have ordered lactose free meals in F and short-haul C before. Short-haul C it doubled as a vegan meal. In F they cater a full on special F meal even with an additional portion of Balik salmon.
Someone else can probably tell you exactly what you’ll get in long-haul C.