I found this family among the Unsourced profiles, and spent the last few days sourcing them and sorting them out from the family of another Philip Young. Everything is consistent, except that every Census record has a different Margaret Young, for a total of four different Margarets. Can I get some expert eyes on this, for a sanity check?
For additional confusion, both Philips came from the same town in Bavaria, and both married women named Kuhn, but they are definitely two different men.
Thanks, Pip, good points! I think there must be at least two. The simplest explanation would be the second one is daughter Margaret. The problem (to me) is that her Census entries are so widely scattered in space-time. Especially the 1860 Margaret, who is ten years too old to be the daughter, and ten years too young to be the first wife. And of course the 1880 Margaret whose birth date is not too far off the daughter, but she's listed as wife.
I've not had much luck finding sources for the daughter after 1850. Maybe because she's right there at home, or maybe because I didn't recognize her in a marriage record without parents' names.