Theodore Lent in New York
Because of Lent's passport application, we know that Theodore and Samuel E. Lent had a close connection. By using these two names and various New York City directories, we can locate where Lent lived and worked--which allows us to pinpoint newspaper advertisements and articles about him. See this document for the directories, the U.S. Census, and my analysis of what we can determine from these documents.
I noticed several things from looking at these directories.
Lent's family ran a stage company. Charles Lent was likely either his father or grandfather. The U.S. Census of 1850 suggests that Samuel E. Lent may have been the father to Theodore (contradicting the newspaper report that identified Samuel E. as Theodore's brother). Moreover, the Census Theodore was 24, but, in his passport application letter from 1857, Pastrana's Theodore also claimed to be 24. Of course, it is possible that the newspaper report made a mistake about their relationship. It's also possible that Samuel E. was the older brother while Theodore was the youngest brother--and that Theodore misrepresented his age.
Lent's Career Before Pastrana
There are a number of newspaper articles about furniture salesman and auctioneer Theodore Lent in 1852 and 1853, which I believe is the Theodore Lent who married Pastrana. I base this on the fact that Lent's office was listed at 495 Broadway, the location where Samuel lived in 1853. Using addresses associated with Theodore and Samuel E. Lent, we can determine that Lent also worked as a plumber.
Lent and Pastrana
This Theodore Lent disappeared from the directories after 1854 which coincides roughly with the time that he began to tour with Julia Pastrana. Many of the locations associated with where Lent lived and worked were close to the places that Pastrana performed.
Note: the Theodore Lent listed as a silversmith and later as a grocer and then clerk seems to be a different Theodore, since he was also listed in the 1853 edition which had a separate entry for the Theodore Lent who lived with Samuel E. Lent.