Chicken and fish are mostly low fat, low carb, wheat free, depending on what you add. Easy to prep ahead then just pop into the oven. You could go ironic and make wheat free "fish sticks" to be in the snacking. Crudités aren't world shaking, look pretty, easy to make and plate ahead. You can make a roasted red pepper dip without fat or wheat, and only the carbs that the peppers bring (char roast pepper quarters, sweat in paper bag, whiz with blender, season to taste). If you wanted to go slightly silly (in a restrained way), you could serve slices of chicken breast, or lean meat, with flights of mustard, the way they do wine or beer tastings, from mild yellow to scorching brown. Have mandolin thin slices of squash, turnips, celeriac, etc., lightly toasted (i.e., browned edges but not floppy) instead of crackers or starchier/carbier rounds.

Or maybe chili con carne? With grilled vegetables? Maybe some all corn totilla chips which are easy for the non-low-carb and lw-carb people to take as suits them.

I agree with Linda about the salmon - so easy and so very tasty. And roasting the vegetables she describes is also very easy and so very tasty. Don't think you can go wrong with this type meal. Can't speak to the tabbouleh, because I have never eaten it.

For snacking within those parameters, I like melon wrapped with prosciutto - if you get a good quality meat and cut any visible fat; cantaloupe is a lower carb fruit. Avocado is a low carb fruit, high it good fats, if that's acceptable, so a guacamole made with non fat yogurt instead of sour cream and low fat dippers (gluten free crackers - I love VAN's brand- or baked tortilla chips) along with veggies to dip.

Tabbouleh wouldn't meet the criteria for wheat free, nor low carb, but maybe that guest could just skip it. This time of year I make a cold marinated veggie salad with fresh green beans, (steamed until still crisp) halved cherry tomatoes, sliced red onion, black olives - or kalamata, artichoke hearts - (I use unmarinated. Artichoke hearts are fairly high in carbs, but can be picked out, or for a lower carb version I use sliced, canned hearts of palm), cucumbers and maybe zucchini, some red peppers.

Marinate in a lemony vinaigrette dressing. Lately I've been making this one and it's been very popular- skip the white balsamic - use a different vinegar, rice wine vinegar is perfect: lemon-basil-vinaigrette

The green beans lose their pretty green if marinated too long, so I usually hold them back and add them just before serving. They are tasty when marinated longer, but just not quite as pretty.

Deviled eggs are another low carb choice, but maybe out for the low fat eater, unless made with low fat mayo and if they don't consider eggs a high fat food.

These are excellent suggestions! Thank you all so much! My mind was blank. I can do a little bit of everything that was suggested and let everyone graze as they choose.

I made "two-bean" salad last week with mostly all low carb veggies. Served with feta cheese and some chopped hard boiled eggs over lettuce--delicious! Beans have carbs but I only used kidney beans, so not that bad of a carb to protein ratio if you ask me. Great make-ahead if you don't want to grill.

I do spinach dip with gluten free bagel chips or rice crackers. Low carbers can have it with raw vegetables.

You can make tabouleh with quinoa which is one low carb thing but I really dislike quinoa so I would pass on that. The red quinoa is the best of the lot, IMHO.

lpm, is quinoa really considered low carb? I googled it earlier (I don't like it either, so wasn't familiar) and found this on livestrong....1/2 cup is not much for a serving and I wouldn't call 17 carbs (the net after considering fiber) low carb, but maybe some do?

"One-half cup of cooked quinoa contains 111 calories, 4 grams of protein, about 2 grams of fat and almost 20 grams of carbohydrates. Low-carb diets count only "net" carbs -- total grams of carbs minus grams of fiber. Because nearly 3 grams of the carbs in quinoa are from fiber, it contains 17 net grams of carbs."

One of my favorite low carb recipes is this Paleo Buffalo Chicken Casserole. You can assemble it ahead of time and throw it in the oven. I like to serve it with ranch dressing and avocado. It is festive, too.

Another idea would be meatballs, lamb or beef or pork or chicken. They can be kept warm in a small crockpot for noshing.

Make spaghetti squash spaghetti using ground turkey in the sauce. A nice salad. Cheese and crackers with hot wings, a bowl of nuts with the drinks before dinner.

Courgetti!