I'm new to the Forum, and I don't have any definite answer to your question, but a possibility.
First, the Schwenkfelder families book (sorry, I don't have the full reference, but it's a relatively well-known genealogy) gives the following (pp. 687, 689):
Eliza or Elizabeth Hartranft, b. 20 May 1779, bapt. 11 July 1779, St. Paul's Lutheran Church, Red Hill, PA, dau. of John Hartranft and Catharine (maiden name not known). Eliza(beth) married Edward Eastburn, 18 Sept 1800. Edward Eastburn was of Philadelphia; unable to verify or trace descendants.
Well, you have some information on the descendants. I have a further question for you. In the data I have collected, I have a reference to someone that I can't locate. Is this someone from this same line?
In the Vineland Historical Magazine (whoops, I don't have the full reference!), there is a transcript of the Bible records of the family of T.K. Eastburn and his wife Nettie Day. There we find the following data:
Wm. E. Eastburn, father of T.K. Eastburn, b. 2 Sept 1817 Isabell Kelly, wife of W.E. Eastburn, b. 17 July 1821
Would you have any idea whether William E. Eastburn is a son of Edward (and brother of your Sarah)? I assume that Wm.'s family lived in the Vineland, NJ area.
Well, apart from that, can we track down Edward's parents? Let me make a speculation, after having tried to sort out numerous of the Eastburn lines. My best guess is that he might have been a son of John Eastburn (and his wife Mary Higgins?), who lived in the Southwark section of Philadelphia (1800 census). This John Eastburn d. in 1806, aged 61 years. The Walton-Reeder book on the Eastburn family indicates only two children for this John, daughters Sarah and Maria. Sarah was baptized in the 2nd Presbyterian Church of Philadelphia in 1772, and Maria was born about 1786, and married William Wells in 1806. I think it quite possible that there were other children as well -- including your Edward? (John Eastburn was the son of Robert & Agnes (Jones) Eastburn, and grandson of Robert & Sarah (Preston) Eastburn.)
Again, please don't take this as a definitive answer -- it's only a possibility, and I have NO solid proof. Do you have any additional information about your Edward that would make this plausible or implausible? (For example, do you know if Edward came from the Southwark section of Philadelphia?)