I did some more digging and came to what I think is the most likely theory of the new Anuna track; I posted my analysis over on GameFAQs Xenogears board;
https://gamefaqs.gamespot.com/boards/199365-xenogears/79713924
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If you read this tweet, Michael McGlynn appears to hint that they are in deed working on music composed by Y. Mitsuda:
https://twitter.com/michaelmcbot/status/1432342467987247117
"Always a huge honour to work with @YasunoriMitsuda
on his incredible music. Aisling was wonderful! Thank you too to Brian Masterson and @MariamAbounnasr
for their kindness and patience."
Could it be the case that Mitsuda, McGlynn and his daughter all were working on a separate project in August-ish? (Apart from the rumored Playstation Remake) Possibly, but all of this seems unlikely if Mitsuda is not himself the composer of the song in any case.
Also it seems there was some confusion that the song might be written itself by Michael McGlynn, as per this report,
https://finalweapon.net/2021/10/08/...-december-according-to-singer-songwriter-ava/
but I think that was a mis-statement on AVA's part and rather he was involved in arrangement, lyrics, and performance of the song with music by Mitsuda/Mariam Abounnasr.
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My best guess right now is that Mitsuda was contracted to write the new Irish-language theme song for an unannounced Metal Gear Solid remake game, possible the first.
Place your bets !!!
My reasoning is based on the wording here:
"
‘Listen, we’re writing music for a remake of a PlayStation game’
"‘Look, it’s an Irish language piece that they’re looking for.’
My view is that this means that the contractor/Sony or overseeing sound director/composer gave the contract to Mitsuda to come up with the new Irish theme song for MGS.
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Addendum: There is a semi-confirmed rumor floating around about a full remake of Metal Gear Solid 3, as well as HD Remasters (again) of all of the MGS games for modern consoles. Might be it is officially announced at The Game Awards, considering the hype level it seems fitting.
Sources;
https://www.videogameschronicle.com...ounced-remake-amid-metal-gear-solid-3-report/