Am I too late to answer this? I always think help-yourself meals are more elegant if you only offer one sort of thing, eg a cheeseboard should be a generous lump of one excellent cheese rather than smaller portions of different varieties, because nobody feels able to take a decent-sized chunk. Also, a theme works well even if it's not obvious. And presentation is important.
I would think about doing a huge plate of antipasti with parma ham and maybe one or two salamis, on different plates if you have enough (these are red meat, technically, but you eat them in v small quantities). On a second plate do mozzarella (buffalo, torn into small lumps) which you can drizzle with some olive oil and torn basil, or if you don't have any basil, pesto mixed olive oil, or just olive oil and freshly ground black pepper; on a third plate put a big hunk of parmesan or pecorino (prised from a larger chunk, ie with uneven edges, not cut with a knife - Carluccio's will do this for you if you can get to one) - serve it with a small spoon and pot of honey to drizzle over). You can freeze some ciabbata to serve warm with all this - tear by hand rather than cut with a knife. You can also serve sun-blush tomatoes, caper berries, olives etc, in different bowls. Ask people to bring some fresh rocket and lots of fresh cherry tomatoes, and the basil if they can get it.
If you want to do something that looks 'cooked', ie as if you have made an effort slaving over a hot stove rather than arranging on a plate: before you go get lots of tubs of ricotta, and some lemons (pref unwaxed) and woody herbs eg rosemary and thyme. On the day mince the herbs (leaves not stems) and zest the lemon, then mix into the ricotta with a little bit of lemon juice and lots of black pepper and some salt, to taste. Put into ramekins or a big, presentable ovenproof bowl and bake for 20-30 minutes til warmed through, longer if it's all in one bowl together. Drizzle some olive oil on top, and serve with roasted cherry tomatoes which you can do in the same oven (vine cherry tomatoes can be kept on the vine for extra prettiness), or those sun-blush tomatoes, plus lots of torn bread, and the antipasti. I know this isn't 'from a Harvester' but it is mild tasting, delicious and impressive. Basically it's just bread, cheese and ham - an Italian ploughman's if you like.
Lastly - remember the wine! Hope you have a good time.