The quick answer to this is NO they should not be merged, they are in fact sisters. Thomas Grey by his second wife Cecily Bonville had 7 sons and 7 daughters, all given by Richardson.
Sons: Edward, Thomas, Richard, John, Anthony, George and Leonard.
Daughters: Cecily, Bridget, Dorothy, Elizabeth, Margaret, Elizabeth, and Mary.
Of the two Elizabeth’s, the first married as his second wife Gerald FitzGerald 9th earl of Kildare and died after 1548.
The other Elizabeth is usually called in sources Eleanor, leading to the confusion on wikitree. In fact, Richardson calls her Eleanor in all of his first edition books (Plantagenet Ancestry and Magna Carta Ancestry), but in his Royal Ancestry series has switched over to calling her Elizabeth. History of Parliament calls her Elizabeth. IMO, she is actually Eleanor, however she is incorrectly called Elizabeth on her monumental brass leading to the confusion. She married John Arundell of Lanherne in 1496, was living in 1502 and dead by 7 December 1503 when John Arundell had a papal dispensation to remarry.
Notes on the profile of Elizabeth Grey-1167 indicating they are the same person need to be erased/rewritten.
Royal Ancestry I:436 (BONVILLE 13: William Bonville m. Katherine Neville)
Royal Ancestry II:168-169 (CHIDIOCK 16: John Arundel m. Elizabeth Grey)
Royal Ancestry III:161-164 (GROBY 13: Thomas Grey m2. Cecily Bonville)