It is none of those, They are all common birds here,
I tried Brown/buff and white as a secondary. However there was little or no white.
I even tried "in trees or bushes" incase it was a rare event for it to be at a feeder.
I have not seen it again. It was smaller than a robin. The robin is a heavier bird in the breast than this one was.
I even tried uncommon birds and found nothing. There was a hermit Flicker ( I see my old post says flinch, I think it was flicker, old age memory) that is close in looks as I recall.
I keep hoping it comes back, With the warm weather we have had this fall it could just be or have been a late migrator.