I'm going to disregard the OP.
My only intent is to focus on cosmetic and aesthetics aspects (or lack thereof).
Please show forbearance for my linguistic mistakes.

1- Roleplay
I think it's still worth mentioning that DnD is about roleplay and the game was praised for its psychological development benefits.
No extensive physical description of your character is required to play the game. And I never met a DM asking for a full description of my character facial traits (who, by definition, is not me).
In the official documentation, information about the physical appearance seems scarce. However it is actually sufficient.
What you need is to differenciate the races and this is done thanks to a very few elements. For some subraces, there is a simple and rather efficient way to identify them, mostly based on colours (skin / hair / eyes).
On the contrary, the amount of information pertaining to the environment, culture, history, religion and psychology is abundant.
You may want to enhance the aesthetics value of this realmlore but generating restrictions based on cosmetic choices would be detrimental.

That is the primary reason why you struggle to find a canonical description of the elven appearance.

Now let me gently make fun of you. Just for a few seconds , I swear.
Over 4 decades, many articles have been published to help players embody characters of all races.
Back in 1982, in the official magazine (which is still published under a different format), you could read this (as an introduction to a long article about elves):

Elves are much like humans in physical appearance. They are thinner and somewhat smaller, averaging about 5 feet tall, but not small enough for the size difference to affect the way elves see humans and vice-versa.
(end of physical description)

That does not prevent elves from having other features as re-highlighted in the description of half-elves but there is no fundamental need to make them explicit.
An interesting point about half-elves is that they are said to be easily mistaken for members of either race, thus substantiating the claim that the differences between humans and elves are kept minimal. There is another contributing factor in the description of hereditary traits potentially found in their human descendants: it's limited to pointed ears and infravision.

Of course, a lot and a lot of lore has been published since then and, back then, the Forgotten Realms campaign setting wasn't published yet.
However why would you introduce more specific physical features? In a game about imagination and creativity, what good would it do?