B.E. I am puzzled about Josiah also. At age 40 in 1850, he couldn't have been the father of Absolum age 32, Stephen age 29 or Lydia age 28.

It is possible that he was father of Nancy age 22, Samuel age 20, Archibald age 18 and John age 14. Also, Sasanna owned real estate valued at $600., Josiah had no real estate.
In 1860 census Josiah's real estate was valued at $1500. and personal property at $1500. Susanna's real estate was valued at $1500 and personal property was valued at $200. Lidya, Archibald and John had no real estate and $400, $400., and $200 personal property respectively.
The 1870 census shows John with real estate valued at $2500 and the others none.

Would a married couple with children together value their real estate and personal property seperately ?

I think Josiah was a son Susanna bore when she was 16 yrs old and the will you mentioned was that of her first husband Josiah Carney who was the father of this Josiah II.

I also think that Josiah II was a widower who moved in with his mother and his siblings and he was a father of some of the younger children in the 1850 household. But I could be wrong lol