1. Since you don't want to celebrate in such a traditional way, then you can celebrate in a modern way. You can even celebrate it as Valentine's Day. Take her out for a big meal, something luxurious and rich, and then give her a bouquet of the most popular Hello Kitty cartoon flowers, and drive her to the beach for a ride. This will definitely add points.
2. I think it's not okay not to send mooncakes since it's Mid-Autumn Festival. At least you should create some atmosphere based on the traditional festival. For example, send a box of mooncakes with exquisite packaging but unique taste. And then add a box of handmade exquisite blessing chocolates, drinking cups, etc.
3. Well, I suggest you still send mooncakes, because after all, it's a traditional festival, and not sending mooncakes will make this festival meaningless. Then send a makeup mirror that girls like, or a plush toy teddy bear or something. This is better.