why not make chicken spag bol. just use chicken mince its yummy i did it one night by mistake the kids loved it lol

and i dont feel its rude to ask for them to chip in with food costs as they have special dietry needs and requirments and it means changing your weekly routine with food.
i woudl also ask they tidy up their room and keep the house as tidy as it is when they arrive.
also ask the wife to help clean, maybe say im happy to cook if you wash up etc etc

just eb upfront with them and honest from the begining.
maybe give them warning before they arrive then if they arent happy let them pay 200 a night to stay somewhere and then still have to pay for food.