Eufemia is pronounced like ew-FEH-mya. The "ew" part is unattractive to me. It doesn't help that "ew" means "that's gross" in English.
The pronunciation for
Sebastiana is not on here, but it might be seh-BAHS-Tya-na which I think is very attractive, in the same vein as
Tatiana.
Name These Characters 1 (over)
https://www.behindthename.com/bb/game/5316320
Name These Characters 2 (over)
https://www.behindthename.com/bb/game/5327763
Name These Characters 3 (over)
https://www.behindthename.com/bb/all/5332744