Your group sounds delightful. Since it is an interfaith event, you may as well bring what appeals to you. If someone else brings samosas, they could be Indian from a variety of faiths or just another foodie who journeys across a wide swath of the planet. Don't worry about it.
Personally, I shy away from fried foods at potlucks because most fried foods lose their crispness when sitting at room temperature. At this time of year, I start looking for anything that isn't heavy- citrus accented foods, clear sauces not rich and creamy, vegetables accented with nuts and herbs.
Whatever you bring, have a lovely time.
With all of our running and all of our cunning, If we couldn't laugh, we would all go insane...
"Changes in Attitude, Changes in Latitude" Jimmy Buffet