I recommend disconnecting Helyas 'The Swan Knight' von Potenburg, (Fictitious Character of Legend) as father of Elimar.
Medlands identifies Elimar as son of a unnamed sister of Huno. "The Historia Monasterii Rastedensis names 'comes Egilmaris filius sororis comitis Hunonis', although there may be some confusion with Count Egilmar [II] as the text also names "uxor sua Eylica."
http://fmg.ac/Projects/MedLands/OLDENBURG.htm#_Toc418239652
In contrast, Helyas is a figure from medieval literature. He appears in Le Chevalier au Cigne (c1192). He is an analog of Lohengrin in the Arthurian legends, and supposedly an ancestor of Godfrey of Bouillon.
https://en.wikipedia.org/wiki/Knight_of_the_Swan
