Coastal Pine?

I've got Falas+thôn. Falathón? The vowel length would reduce, right?

I get Falasthon from ɸalasse-θāne. θāne > θǭne > θaune > θone Because [au], [ae] became [o], [e] in polysyllables.

Hm. The s and th don't blend? It feels a bit cumbersome to have both next to each other.

-sth- is attested in Noldorin (=draft Sindarin), in Cristhorn; however there are no relevant examples in mature Sindarin. I would tentatively guess that this cluster is still permissible in mature Sindarin because that is what we arrive at by formally following the phonological rules that we do have, and in my opinion it is also supported by -sf- in Asfaloth. However it would also be equally fair to say that -sth- should be avoided because of lack of attestation in (out-of-universe late-) Sindarin and because the analogy with Asfaloth is only partial at best.

That being said, I also don't really have any alternative to offer here since we don't have other words for "coast". You could reverse the elements to creat Thophalas, but that would normally mean "piney-coast" instead (and I don't really like its sound either). Tophalathren with an adjectival ending would clarify it as "coastal pine", but it sounds a bit long and heavy this way (note that medial 'ph' stands for a geminated [ff]).

Hm. strokes chin I'm trying to come up with a name for a Silvan Elf who lives in Edhellond. Coastal Pine was the best I had (Celeborn means "Silver-Tall" so I didn't feel that bad about how odd it might be for a name). Sea-bow, perhaps? He's an archer. Gaearcú? If we know anything about Nandorin perhaps we could work in a Sindarization of their term for bow, cogn?

Celeborn is "Silver-tree"; it is true that the very literal meaning of ✶ornā was "uprising, tall", but the word semantically drifted and merged with ✶ornē to mean, specifically, "(tall straight) tree".

Danian cogn (adj.) "bowed, bow-shaped, bent" is derived from ✶kuɣnā, and a cognate of Noldorin (=draft-Sindarin) cûn of the same meaning. The later would need to be updated to Sindarin phonology, which is not the easiest in this case, but IMO it would likely end up as coen (though at the same time its root ᴹ√KUƷ should be updated to √KUH, and with this in mind it might end up as cûn/côn again). Anyway, using this would give you "bent-sea", which makes little sense.

"Sea-bow" would be either Gaerchu or Gaergu.

lol Chu again, huh? Too Pokémon sounding. Gaergu just sounds funny. Ugh, why are names so difficult? Sea-tree, Gaergalad? Strict Sindarin would be radiant sea but he's a Nandorin elf so his interpretation of Galad would be tree?

Tree is galadh (<✶galadā), whereas as "radiance" is galad (<✶ŋgalatā), so not really confusable. Gaergalad would specifically be the latter, "sea-radiance", whereas "sea-tree" would be Gaeraladh.

Galad is tree in Danian per www.elfdict.com

It is "tree" in Nandorin, which is not quite the same as Danian. Anyway, we don't really know enough about the Elvish languages beyond Quenya and Sindarin to construct names in them (or at least I don't).

In this particular case, note, the final consonant is not the only difference between the Sindarin compounds for "sea-radiance" and "sea-tree" - Gaergalad & Gaeraladh respectively.