As always the answer in this fandom is “Telperinquar, unless you look deeper, in which case maybe it’s Tyelperinquar, unless you look deeper, in which case it’s entirely about what you think would have been the fictional political affiliations of long-dead underspecified Elves.”
Does ‘Tyelperinquar’ exist
in that form in Tolkien’s writing? This
is the given Quenya translation for Celebrimbor in Helge Fauskanger’s
Quenya-English wordlist (which I generally trust above all others), but I’ve
always wondered if this is either a typo or an editorial correction – the
references cited in the wordlist do not have this form.In addition to the sources
you’ve cited, we have the following in Parma
Eldalamberon XVII, p 42, Celebrimbor: ‘The Quenya equivalent was Telpinquar, or Telperinquar.’In a strictly Quenya sense,
Telperinquar would be Tyelperinquar. (This
suits my headcanon, and I like the sound of the word better. If in doubt when speaking Elvish, always go
with the best sound. The Elves would.)Telperinquar is what I’ve always seen, too (I was pretty bewildered at first to say Tyelperinquar/Tyelpe so widely used). Tolkien does say in UT that Telerin telpe was adopted into Quenya and more common than tyelpe, since the Noldor admired their skill as silversmiths. Fauskanger refers to it in his discussion of Telerin. So it’s Telperion and not Tyelperion, and likewise in the frozen Quenya of the Númenóreans: Telperiën, Telemmaitë, Telemnar.