Since Ive already heard them speaking (in my dream) Ive been trying to find the closest voice within people/singers/actors/voice actors and couldnt find any that is exactly the same.
The closest ones Ive found so far are japanese and latinamerican VAs (and still there are some nuances they would never get from the trio voices)
Liar: Ricardo Mendoza (Shiryu-SaintSeiya) ; Muyo Irino (MobPsycho100) [The closest ones on juvenile playful voice but still lacks some smoothness or mellow nuance in their voices to get closer to Liar's real voice]
Ira: RenĂ© GarcĂa (Cisne-SaintSeiya), Ricardo Tejedo (Zabuzo-Naruto); Junnichi Suwabe (Aomine-KurokonoBasket/Tseng-FF7 series) [They are still a bit raspy but closer to the young yet deep Ira's voice)
Caelis: Alejandro Graue (Jonas-Dark/Sky-PowerRangers SPD), José Manuel Vieira (Alucard-Hellsing/Ukyo-samurai7/); Moriyama Toshiyuki (Ubuyashiki-Kimetsu no Yaiba/Kazuma Sohma-FruitsBasket) they still need a more softness and real sadness hints in his voice a bit deeper, nostalgic and kind
Since Caelis sings, his singing voice is kinda like this: Fr. Gennaro Becchimanzi or the choir lead male voice I couldnt find his name I Peter Hollens I