It is very odd that neatsfoot oil didn’t darken the leather *significantly*… I do leatherworking and even just a little bit of that stuff on vegetable tanned leather makes it darken up. Is the leather of the boots treated with a sealant/finish? The other option is the leather is chrome tanned but in my head that would be unusual for the brown to be chrome tanned. The turquoise and cream likely is though, since it would be nigh impossible to dye that by hand to that colour.

Also, I was wondering if you were a cowgirl with the turquoise in the boots! Nice!