Using City Directories to find William Rowan

I have very little information about my paternal 3x great-grandfather William Rowan.  I haven’t really known where or when he was born or died.  I know he and his wife Ann Meenan had a son John William Rowan (my 2x great grandfather) in 1846 in Troy ?  (according to John’s marriage license). 
 

I have found the following;  (you can click on image to enlarge)

                              1848 Doggett’s NYC Directory page 352                                 1849-50 Doggett’s NYC Directory page 364

            Rowan Wm. harnessmkr, 268 Av, 6, h. W. 24thn. Av. 6              Rowan Wm. C. harnessmkr, 268 Av. 6, h. 62 W. 24th     
   
Then I was able to find :
                                     1850 US Federal Census Mortality Schedule                                                              1869 NYC Directory

line 12- William Rowan male, age 35, Married, Estimated birth year-1815,                          Rowan, Ann, wid William L. h 287 Tenth av.
birthplace-Ireland, occupation-laborer, cause of death-dysentery,
death date Aug 1949, cause of death-dysentery for 7 days
line 13- William Rowan  male, age-1/12, birth year-1849, birthplace-NY,
death date-Aug 1849, cause of death-poisoned?(hard to read), 1 day

Well, have I found the right William Rowan?  I’m not sure. 

• I have no official middle name for William and there are several on the Directories.  At some point I thought it was Henry but on son John’s marriage certificate it just lists his father as William Rowan.  There is a Wm C. on the second of the Directory and in the last directory is says Ann is the widow of William L.  Hmmmm……  I wonder who gave the information for the Directory?
• If I found the right William Rowan then I now know that he was a harness maker and where he lived in New York City.
• I know that when John got married on 1 Aug 1869 (to Sarah Hughes) his address was listed as 239 10th Avenue which is close to his mother’s address listed above in the City Directory-287 Tenth Av.
• My great-great-grandfather John was reportedly born in 1846.  It would make sense that another baby would have been born to William and Ann in 1849.  How sad to know the baby died in August when William also died.  How would the baby have been poisoned if he was only a month old?  An accident?

Still so many questions to find answers to.
I would appreciate any additional information or corrections you may have.
Enjoy the journey,
Debby