White Faced Black Spanish Bantams do exist. Privett Hatchery sells them:
https://www.privetthatchery.com/product/970
I think some feed stores order from there, so just walking into a store and finding them is possible.
That is one source in the USA. I don't know what may exist in other countries, or which country we are talking about here.
All good thoughts. As regards the feet, I have gotten birds with that amount of feathering from parents that had clean legs and were of clean-legged breeds. So it might not mean any recent mixing with a feather-footed breed.
Yes, all of those could be possibilities. If you are in the USA, Old English are more common than the others on that list.
Some of the earlobes look bigger than what I would expect on Old English, I don't know whether there are bantam versions of Andalusians, and I haven't seen blue in the White Faced Spanish. So I'm inclined to think they are a mix of some sort, but I can't be positive about that.
If they were bought at a store or directly from a hatchery, they are more likely to be specific breeds rather than a mix. If someone bred them from a backyard flock, a mix is much more likely. If one parent was a White Faced Black Spanish and the other was a Blue Old English, I think that would give birds like you have in the photos.
Rosecomb bantams also come in black, blue, and splash, and look similar except for having a rose comb. So if those birds are a mix, Rosecomb is another breed that could be involved.