Dinner for 25 - Crawfish boil? Polenta? Tagines?

If you do want to make paella, if you stop when it's pretty much done but you haven't done the high-heat soccarat-creating last step, you can hold them at room temp for a while and then put them back on the heat for a few minutes to reheat and make the soccarat right before serving. They hold up really well that way; that's how I've made two paellas on my single paella grill. It's my favorite food to make for a large gathering.

another option is a few different pastas and salads

For one large gathering I made assorted pizzas. Prebake the base pie , add the toppings and finish in the broiler. the pictures shows them before going into the oven. From the bottom: meatball / prosciutto with smoked gouda fig jam & figs / ricotta with brocolli rabe and fresh tomato, lastly, sausage, fresh mozzerella and spinach.

https://en.wikipedia.org/wiki/Rijsttafel. Have never done it but it sounds impressive...

Tagines, stews and curries are a great idea, because you can make them ahead of time, they serve a crowd, and having several different options with warm pita bread or couscous will get folks excited. If you do three different pots that are thematically tied together you can then cover both meat lovers and vegetarians and offer people diversity. For example, you could go with "along spice road" or "flavors of north Africa" theme if you want to focus on spices, or "harvest" if you would like to leverage the abundance of all beautiful produce that's available in early October (think eggplants, squashes, peppers, tomatoes, corn, pumpkins).

Another option that you could do ahead of time is a variety of stuffed vegetables: stuffed eggplant or imam bayildi, stuffed peppers and tomatoes. You can use a variety of stuffings - rice, quinoa, bulgur, other vegetables, corn, nuts and ground meat. Serve with yogurt, or a variety of flavored yogurts, like lemon tahini, herbed yogurt, etc. Stuffed veggies also make a great presentation

Here is an option:
stuffed eggplant with pomegranate sauce
zucchini stuffed with bulgur, peppers and roasted corn
stuffed cabbage
dolma with lamb, lemon, pine nuts and rasins
tomatoes stuffed with rice and spicy chard

Some suggestions:

Baked potato bar
Taco bar
Korean ssam (lettuce wraps) served with a table of banchan (side dishes)