I would expect them to add the Sephirot, Nidhogg and Sophia birds to Bertana's shop in 3.45, if they were going to continue releasing them in three's. They likely will wait to add Sophia's until a later patch, however. It would be nice if they'd let you purchase the mounts with 99x totems right away, since I personally am against the RNG nonsense (seen way too many bad players get the mounts). Being a skilled player and having done 112 runs of Sophia and losing on 11 birds, I'd much prefer something that requires effort as opposed to something that's sheer luck.