] I believe that if Darcy had brought more people than the Bingleys, JA would have at least mentioned that there were other ladies/gentlemen there.

Mr Darcy had been by the river with Mr Gardiner and "two or three other gentlemen from the house"(chapter 45). That would indicate that the party consisted of a few more gentlemen at least. If the gentlemen had been Mr Bingley and Mr Hurst the text might have mentioned them by name.