Is the plural of Siamese Siamese?

For the past five or so months I've been feeding behind a rooming house in a not so desirable area of town.  Andrea and I have really cleaned up the situation there, we've taken out a few tame ones and spay/neutered others.  There's a friendly Siamese who's been around for a while, and we thought he may have a home in the rooming house but this winter he's been out a lot.  Last week in the frigid weather he was outside day and night, and would frantically follow me to my car.  Andrea and I broke down and brought him in.  We've put up signs but nobody has called.  Siam as we've not inventively called him is a sweetie, a bit shy and high energy but today when I brought him back from his neuter he curled up in Andrea's lap.

Bizarrely there has been another Siamese that appeared about a month ago at the same location. Although neither Andrea nor I could get near him we both said this cat isn't feral.  He looked cold and unhappy.  Thankfully he was easy to trap and so suddenly Andrea had two Siamese at her place.  The Siameezer (yes another great name) turned out to be better than we had hoped.  Not only is he not feral he's really friendly, almost instantly he was purring and happy to be patted.

I really can't explain why there was two friendly homeless unneutered Siamese in the same area, but they are both now safe and warm, and I expect will find forever homes very soon.