Everyone is going to eat the shrimp, so if you don't want everyone to eat it, don't serve it at all. Seriously, just cut it from the menu.
If you want something interesting besides veggie burgers, make a quinoa salad. I make mine with olive oil, lime juice, avocado, tomato, and a few other things I can't recall. Cut the avocado if it's too expensive. Quinoa is high in protein, and my vegetarian people love it. Another option, if you don't want a million salads, is to put a quinoa salad inside mini bell peppers and cook it on the grill. They will look fab on a platter.
Cheaper fish option: cut shrimp up and mix with rice and spices. Serve in the mini bell peppers. Now you're serving shrimp without giving a few whole pieces to everyone.
Another option, if you really don't like the veggie burgers, is to make a big homemade mac-and-cheese as another side dish. It adds protein and fills guests up, without meat or major expense. Use interesting cheeses, like gouda, to make it more sophisticated.
Deviled eggs. Enough said. We covered them in another thread.
If you want to switch up the hot dog/hamburger thing, do chicken thighs or drumsticks on the grill. They're cheap and easy, and people love them.
Potato salad for people who hate potato salad: cut baby red potatoes in half or quarters, depending on size. Boil. Cool. Mix with balsamic vinegar, olive oil, and loads of chopped parsley, scallions and chives. It's fabulous.