Curt Hofemann, curt_hofemann@@yahoo.com, has one source indicating that Elizabeth is the same as Sybilla, wife of Alexander of Scotland. Possible (she probably would have married Fergus after 1124), though I think unlikley. Curt's other source has them as two different people.
Possily your ID I04761 Sybilla FitzHenry & this Elizabeth are one & the same. There are conflicting sources:
Same:
Sibyl, but called Elizabeth by Sandford [Ref: Sheppard Apr65 p96] unfortunately I did not note the identity of "Sanford" in my notes... Curt
Not same:
He married Elizabeth, natural daughter of Henry I, and sister of Sibilla, who married Alexander I, brother of David." [Ref: Sir Herbert Maxwell, "A History of Dumfries and Galloway" by Sir Herbert Maxwell, Edinburgh, 1896, pp. 47-48]
Regards,
Curt