I think you should say the names and terms in whatever way they sound to your mind's ear while you're reading, but here's how I hear them, since a bunch of people have asked. Sometimes I'm not even sure which pronunciation I prefer! And regional accents differ throughout Eiden Myr, so the characters aren't pronouncing the names exactly the same way, either (just as my name seems to rhyme in the Midwest, but not in New York City {g}).
Eiden: EYE-den
Ennead: EN-ee-add
Galandra: gah-LAN-dra
kadra: KAH-dra; kadri: KAH-dree
Morlyrien: more-LEER-ee-en
pethyar: PETH-yar
sowmid: SEW-mid ("sew" as in needle and thread)
Sylfonwy: sil-FAHN-wee
triad: TRY-add
triskele: try-SKEEL (triss-KEEL also works)
Amaranth: AM-a-ranth
Befre: BEF-reh
Benkana: ben-KAH-na
Breida: BREE-da
Bron: brahn
Dabrena: da-BREE-na
Danor: DA-nor
Daughan: DAWg-khin ("gh" is somewhere between a "k," a hard "g," and a glottal
"ch")
Evonder: eh-VON-der
Ferlin: FUR-lin
Freyn: frain
Geara: GEE-ruh (Gay-AH-ruh also works)
Gondril: GAHN-drill
Graefel: GRAY-fel
Hanla: HAHN-l(e)
Jerize: jeh-REEZ
Jhoss rhymes with "moss," soft "j"
Jimor: JIM-or
Jonnula: JOHN-you-luh
Karanthe: kah-RANTH
Kazhe: cahj (soft "j")
Keiler: KEE-ler
Landril: LAN-drill
Lerissa: leh-RISS-a
Liath: LEE-uh
Marough rhymes with "barrow"
Megenna: meh-GEN-ah (hard "g")
Mellas: MEL-as
Naeve: nave
Nerenyi: neh-REN-yee or NEH-ren-yee
Nole rhymes with "goal"
Pelkin: PELL-kin
Portriel: pore-TREEL ("pore-tree-ELL" works, too, and is pretty)
Roiden: ROY-den
Seblik na Lareon: SEB-lick nah LAR-ee-on
Seldril: SEL-drill
Selen: SELL-en
Terrell: teh-RELL
Tolivar rhymes with "Oliver" (TOE-li-vahr works, too)
Torrin: TORE-in
Verlein: ver-LANE
Vonche: vawnsh
Worilke: wor-ILL-keh