甄 (Zhen)
Gyeon (甄) is Chinese Korean surname, it text has two Chinese dialect a Zhen and Jian because by change of dialect a 甄 by Sun Quan (孫權). also, Korean too, has two dialect Gyeon and Jin. Hwanggan Gyeon (甄) family from China.
in the Hubaekje, Gyeon Hwon (甄萱) is not Gyeon family because his father and son no use surname Gyeon, thus Gyeonhwon (甄萱) is just name. by book of samkooksaki, Gyeonhwon (甄萱) father has family name Yi, his son name is Shin Gum (神劍).
堅 (Jian)
Gyeon Quan (堅權) is General of early Goryeo 10th AD. Gyeon Quan do win have attact a Mohe (靺鞨), also break a Shin Geom (神劍) of Hubaekje.
unknown a fact of Gyeon (堅) family. just, the old book of Korea has mistake of that use a han text.
References
Gyeon Wikipedia(Text) CC BY-SA