Strangles or Not?

Okay guys, I have a serious situation at my barn. I'm just going to give you all the details and let you run with it. I want thoughts, impressions, opinions, whatever... This is a huge barn, about 50-60 boarders + the owner's 20 horses. I brought a horse in exactly 21 days ago. Arrived on Friday at 7am. He's a coming 3 year old gelding, out of Missouri. He had a rough transit. Was picked up on the preceding Tuesday, and trailered down to Kentucky, where he overlaid for 2 days at a farm in Lexington. Haulers were switched, but both professional rigs. He begins trailering to me on Thursday. Rig is late and horse overnights in trailer and comes in at 7am on Friday morning. I take him off that trailer personally and walk him to his isolation paddock. There are 2 isolation paddocks. There is another horse in the adjoining paddock, a chestnut gelding who was taken out of an auction. Paddocks are ringed with hot wire on all sides and have an aisle between them. The two horses cannot touch. After a day or two, barn owner informs me she has heard my horse cough. She believes it is only transport stress. Cough seems to disappear after another day. Two weeks to the day after he came in, he and his neighbor are released from their isolation paddocks and put in the arena field, which borders the field where the main herd is kept. This is preliminary to them being released into the main body of the herd. The next day, I see them pulling a nose swab off his pasturemate, the chestnut gelding. I am IMMEDIATELY concerned. I am told strangles was already ruled out based on a previous swab, but this horse still has a respiratory "thing" and they doing another swab and a culture. I question why they were turned out together and exposed to the herd if this is still going on? No real answer. On Sunday, I notice my horse has a runny nose, but fluid is minimal and mostly transparent. I leave the barn owner a message. Fast forward to this Wednesday. I get a message in the late afternoon to call the barn owner on her cell phone. I call. She gives the news - they think my horse strangles. Of course, my heart sinks to the bottom of my shoes. I go and talk to her. Dentist was out that day, and they pulled my gelding in to check his teeth. She says he was coughing, had a temperature and enlarged nodes. They lanced them, gave him antibiotics, left flush, cephalexin and naxcel for me. The attending veterinary left notes that they pulled tan colored pus and chunks from the nodes. Barn is under voluntary quarantine while we wait for the culture results. Meanwhile, as you can imagine, I am HITTING THE ROOF. I question barn owner closely about my gelding's pasturemate. He was tested, she said, for strangles off a nose swab when he first came, as well as with the follow up the past weekened. Results say he has Strep. zooepidemicus and is currently on antibiotics. She claims she had the vet look at both horses and it was the vet who said they could be released from isolation. She thinks my horse carried it in from his haul. My horse is back in isolation. His pasturemate stays in the arena field. I have talked to the vet who was on hand at the time. She believes it is strangles and was dormant until now. My horse has a temperature. I have not heard him cough. He has no nasal discharge and is not off his feed or acting sick. If it is strangles, it appears to be a mild case, at least. I am in favor of letting the infection run its course and keeping him comfortable. She wants to treat with the naxcel and flush the nodes with cephalexin. I am questioning whether this is an alternate strep infection picked up from his pasturemate, as it appeared 5 days after they were turned out together.