I am not descended from John. I am the webmaster and unofficial historian of the Wertman Family Association and Catherine (Weber?) Delong Wertman has long been one of my most wanted. Anything George Philip related is of interest to us and I have been on a lonely research trail until you appeared. I have been in contact with some pretty serious Delong researchers and they just will not accept Catherine's words, "my beloved son" as exact. They prefer to believe she meant son-in-law and that John's wife, Catherine was a Wertman.
The Candace Anderson book (your source #1) has a case where a John Delong found an error in an estate accounting and objected. I figure he must have been a son-in-law and it affected his share. I cannot find my copy/notes, but looking backwards to the original filing, the deceased did have a daughter, Katherine. Until someone shows me otherwise, I will consider that to be the younger Mrs Delong's surname. Sorry for the lapse, but my office is a mess and thing go missing all the time. It has happened before and will happen again.
I was under the impression that they migrated to Sunbury c1785. Not sure where I got the notion. On 26 Sep 1786, Catherine Wertman of Sunbury sold assorted household items to John Arthur of Augusta Twp (Bill of Sale recorded 27 Sep 1786, Northumberland Co, PA Deed Book C, Page 342). I have been in contact with a researcher interested in John Arthur and he knows of no family connection, so I presume a simple business transaction. As such, I also had in my notes that Catherine was of Sunbury when she gave John the 1787 PoA. I thought I had a photocopy, but cannot find it.
I found the copy of the Union Co document where John Long was arranging for future care of a daughter, Elisabeth. It is very complicated and I cannot see what exactly is going on. We do not even know this is our guy. The John of Lynn that abandoned his family is a case in the Candace Anderson book. Again, I have a copy, but cannot locate it. I have had no luck at all in folowing the descendants forward. I thought I might have found one of the sons, Henry or Daniel? just across the river in Montour Co as Long, but could never do anything with it.
I have always had the notion that I might be descended from Abraham Delong. My ancestor, Leah Stroup married George Wertman. Her parents are probably Joesph and Barbara Stroup of Mahoning Twp, Columbia (now Montour) Co. Joseph is probably the son of Andreas Straub Sr and Catharina Delong, who is a daughter of Abraham Delong and perhaps, Catherine Weber. The problem is Catherine's age which is given at http://www.minerd.com/memoir-bauerbarbara2.htmhttp://www.minerd.com/memoir-bauerbarbara2.htm. See Generation Two, #1.7 and ignore the notation about an Englishman. The author acknowledges that error.
A good age analysis of Abraham's children needs to be done to determine, if there may have been an older wife.