Thai food is perfect as far as dairy-free food goes, and it can be made low-FODMAP quite easily as well. This is a variation on a meal I make at least once a week. We often have a carton of coconut milk in the fridge (see Milk Alternatives). I wouldn't use this type of coconut milk in a thai curry but it works well adding a small amount in a stir-fry type dish. Caution: According to the Monash app, coconut in various forms contains FODMAPs however in the quantities in this recipe it should be tolerated by most people.
You can get dried kaffir lime leaves in the herbs and spices section of a supermarket, but they are not a patch on the flavour of fresh ones. One of my best ever purchases was a kaffir lime leaf plant, which I bought online from Wholesale Kaffir Limes. You instantly get an authentic Thai flavour just from one or two leaves.
I have also used a spice mix in this recipe from Fodify Foods who I heartily recommend for a range of spice mixes and low-FODMAP sauces. If you can't get hold of this then some black pepper will do.