Well, that’s a different kind of transport consideration 
Do you know if your vegetarian friends eat eggs? (Many of my friends & family don’t.)
I love gougeres, especially if you can warm them up before serving.
Apero bread / savory cheese bread is similarly great with cocktails. Here are some versions I like.
Puff pastry roll-ups are a bit more work but wonderful. Like this or this. A stuffing of potato and cheese with some heavy seasonings (zhoug, calabrian chile paste, green chutney) works nicely, or spinach and cheese.
Mini quiches or a slab / sheet pan quiche sliced into bite-sized squares, or kuku (spinach is easy), or impossible quiche bites all disappear fast.
Dips are easy, cold or hot. Pimento cheese or spinach & artichoke for example.
Or a small wheel of brie or camembert topped with something (hot pepper jelly or honey & sriracha or caramelized onions) looks and tastes fancy – put it in the oven (or microwave, low power) when you get there to get it melty.
Too bad you don’t like mushrooms – mushroom pate is fabulous (lentil and walnut pate pretending to be foie gras – aka faux gras – not so much 
).
