Earlier today/yesterday in Japan, someone on 2ch posted a link to an image of all the Japanese voice actors - with some of their more prominent roles in anime, games, dubbing, etc., credits listed - known so far to be in the Japanese cast of Final Fantasy XIV: A Realm Reborn (names are written in Japanese and Roman letters):
Most of their roles in FFXIV:ARR have not yet been identified or revealed.
My expectation and own ears have been confirmed by Japanese fans that Tanaka Atsuko does indeed voice Merlwyb (role not listed in the above pic) in FFXIV:ARR:
【1080P】FINAL FANTASY XIV "CRYSTAL'S CALL" トレーラ
Some Japanese fans find the above trailer on Nico Nico Douga amusing because Gaius, voiced by Ootsuka Akio, reminds them of Metal Gear Solid.
Ootsuka voices Solid Snake in the Japanese version of the Metal Gear Solid game series.
Among the comments scrolling across the above video, Japanese fans praise Tanaka Rie's performance of the savage, bloodthirsty primal Garuda as an "excellent insane Garuda" ("Garuda no hakkyou ii na") and "the best" ("saikou") in the Nico Nico Douga video above, though one thought too much audio processing had been done in the studio (which would also be the case for Garuda in the English, German, and French versions, which I have also heard).
But Tanaka Rie speaking in Garuda's voice live with nothing but a microphone does sound a lot like Garuda in the FFXIV: ARR "Crystal's Call" Trailer video above.
If there is one thing Tanaka Rie - who voices a lot of sweet, gentle characters like Lacus Clyne in Gundam SEED, Chii in Chobits, Maria in Hayate no Gotoku!, and Ciel in Rockman Zero / Mega Man Zero - is known for, is that she voices many antagonists and great evil, often crazy, insane and sadistic villains in anime, games, etc.: Suigintou in Rozen Maiden; Tomoe Marguerite in My-Otome; Liang Qi in CANAAN; Yamanobe Sayara in Mnemosyne; Morganna Mode Gone in .hack//SIGN; Nomura in Higurashi no Naku Koro ni Kai; Haibara Sakuya in Fatal Frame 4; Helga Neumann in Phantasy Star Portable; Mariabell Crois in The Legend of Heroes: Ao no Kiseki; Aizono Mio in To Aru no Railgun (PSP video game); Virgo Zodiarts in Kamen Rider Fourze... and now Garuda (along with her polar opposite, the good, wise Padjal Elder Seedseer Kan-E-Senna) in FINAL FANTASY XIV: A REALM REBORN.