re ten tribes
Almost certainly there were refugees from the northern kingdom who went to Judah - thats sort of logical given whats happened in other historical cases, plus it would account for what appear to be "northern" stories in the bible (IF you accept the doc hypothesis, or anything resembling it). So to some extent the descendants of the lost tribes are todays Jews.
Its also likely that the historical Samaritans have some ancestry from the "lost tribes" The bible states that the Assyrians took them all away, but that would go beyond what the assyrians generally managed to accomplish, IIUC. The bible also states that the Samaritans knew some Hebrew customs, etc because they needed them to deal with the animals of the land. Lets just say that if that is NOT credible to you, then its likely that the Samaritans WERE of Israelite descent (certainly modern Samaritans think so). So the descendants of the 10 tribes would include modern Samaritans. Since a significant number of Samaritans were (forcibly) converted to Islam in the middle ages, some of the lost tribes are probably Palestinian arabs, at least those from around Nablus.