I see that I left something out of my list, though - thanks for pointing it out! At the end of the next chapter, we are told that Mr. Gardiner had arranged to meet *some* of the gentlemen at Pemberley by noon to go fishing, which implies that not all the male guests went fishing. Then, in ch.45, we are told that "(Darcy) had been some time with Mr. Gardiner, who, with *two or three other gentlemen from the house*, was engaged by the river, and had left him only on learning that the ladies of the family intended a visit to Georgiana that morning." So, the "two or three gentlemen" do not include either Darcy or Mr. Gardiner.

Only the ladies are mentioned in the drawing room scene, because it's a matter of ladies calling on ladies, nothing to do with the gentlemen guests Darcy has brought with him.