I seem to have a chocolate Wyandotte bantam with many of the issues you stated.. Eggcessive. She has watery/ foam eye.. sneezing.. wheezing. The watery/ foam eye seems to have disappeared since I brought her in the house. She has a wheeze and sneezing still. She is eating and drinking. Acts quite normal.
She was with 20 other girls, 3 ducks and on cold nights joined by two Super African geese, and 8 roosters in the next pen. 5 peafowl in a pen at the back of the barn too. No other bird shows any sign of what she shows.
I'm hoping the other things you mentioned, nasal drainage, gasping, rapid breath and any swelling on her face isn't going to hit her too. I have her in a rubbermade tub in my family room a few feet from my wood burning enclosed fire place. So plenty of heat..
I live in Canada and some if the things I see mentioned to treat her I don't have access to. I do have poly-tonine a complex. ( vitamins)..that I have in her water. With that I did read that antibiotics may not treat what she has..
if I'm missing something feel free to add what you think .. it's always appreciated.