Well, I would say that the Singer date you have is wrong. That 28 handcrank is beautiful but they were not made that early. it's serial number looks like 10263672 that is 10,263,672 which is actually 1891
Because I would personally have an interest in that, i'll refrain from discussing value here. feel free to PM me and I will give you my email so it could be discussed off-board
The White serial number would be FR (Family Rotary) if you call the Husquvana folks, they can tell you the White's age (they own white and the records)