Your Ely Ongs are the first I've seen in that town, though that's not saying much. I know of a FNU Onge who had sons John and Edmund Sr. (DPOB 1545, Lavenham; m. Elizabeth Ladyman, 1540, Lavenham). John had at least one son Francis (DPOB 1612, ?) who father was in Hartest, Suffolk, when Francis was admitted to Cambridge Univ. in 1632. Francis went to New England in 1631 but appears to have returned almost immediately though this requires further analysis. Francis had three sons, Francis (DPOB 1633, New England), John (DPOB 1636, Peldon) and Jeremy. He was married to Bridgett and died in 1666, possibly of the plague, while rector of the church in Peldon, Essex.
Edmund Sr. had a son Edmund (DPOB 1575 Lavenham, Suffolk) who married Frances Reed and she or they went to New England. Edmund Jr. may have died in 1630 in England.
Francis the rector's movements don't quite make sense to me and generally consider this a tentative account of these people.
Hartest was in the Diocese of Ely and the bishop may have been instrumental in effecting Francis's entrance into Cambridge. There were a few other Onges in Cambridge. (See http://www.archive.org/details/p1alumnicantabri03univuoft
I'm aware of a William and an Adam Onge, among others in Suffolk and Essex. I've nothing terribly reliable to relate about this just now.
Where did you see the "Ing" version of the Ong name, please?