It seems that at the time of writing
The Lord of the Rings (or at least in the time 'surrounding' this general period) Inglor Felagund had a wife and children, and in notes to the QS manuscript even Gil-galad was his son. In early workings of
Of The Rings of Power And The Third Age Galadriel was a daughter of Felagund the fair (and the elder sister of Gil-galad).
The conception that Inglor had no wife arose in the early 1950s in any event, in
The Grey Annals. Even
after this statement in
GA, Tolkien, perhaps mistakenly, gave Felagund a son, Artanaro Rhodothir ('Orodreth'), but then noted that Finrod
'had no child (he left his wife in Aman)'. And in an isolated note dated 1965:
'Finrod left his wife in Valinor and had no children in Exile.'
I don't think Tolkien had even printed the name Inglor* (as a name of Felagund) in the first edition, and so readers would not think of Gildor as
Inglor Felagund's son even in the 1950s. It's really a case of readers being shown (by CJRT) certain draft texts, otherwise Gildor as the son of (some Elf) named Inglor is not problematic.
Galadriel55's post in
'Ever wonder...' inspired me to come back to this.
Thus one a side note I'll add: not that Galadriel55 said otherwise, but
Fingon does not really mean 'Lord of Hair' as I take the explanation. As a Sindarin name it might be interpreted 'Hair-shout', as JRRT notes in the essay (the word
cáno meant 'commander' in Quenya), but even the Quenya name
Findecáno didn't really mean 'Hair-commander' as much as it was the word 'commander' with
fin(de) added on -- as an echo of an ancestral name --
'and if this was also specially applicable it would have been approved as a good invention.'
And it was suitable for Fingon, since he wore his long dark hair in great plaits braided with gold. In short, the 'meaning' of the name elements
together is not really the point with respect to Fingon... if one is wondering why such a odd seeming name exists that is.
_________
*even if he had, there could be more than one Elf named Inglor, just as there seems to be more than one Elf named Rumil in
The Lord of the Rings.