Honestly? I think you're going about this wrong.
30 people is A LOT, even if 1/3 of them are kids. You need to outsource when you have that many people to provide food and drinks for.
You also have to remember that in a party atmosphere, when someone else is catering, people tend not to treat the food as they would when they're paying in a restaurant or have been invited over for lunch (just them). People don't always think about others, they will pick and choose whatever looks goods so you end up with tonnes of some things left over and not enough of the other and so on and so forth. There is sometimes a lot of wastage, too.
There's also a lot to coordinate between drinks, food, cutlery and plates and bowls and napkins/tissues, and glasses and water and tumblers, and spillages and breakage, people in and out of the loo all day, a tonne of washing up after. You also want to enjoy yourself!
So, don't think of this as feeding two families and scaling up. Think of it as mass catering and scaling down. Buy in platters of veggie foods from your Turkish place: falafels, hummus, dips, olives, vine leaf rolls, couscous. Order in your pizzas and get sides: garlic bread, veggie pasta, mac and cheese. Buy cartons of juice and jugs of water. Buy more bread and naan than you think. Do as little food prep as you can. Consider the size of your oven and your hob and your fridge. Do cheese platters; buy Costco sized bunches of grapes. Buy a watermelon and slice it up.
Do NOT experiment with new recipes. Don't spend ages cooking because with that many people around people don't notice the food as much as they notice the company. Don't present fancy-looking food because you won't get the attention it deserves.
Your priority is the company. Mass cater. Give doggie bags of leftovers.