In [name_f]English[/name_f], I would pronounce them…
[name_m]Asa[/name_m] —> AY-suh
[name_m]Andre[/name_m] —> ahn-dray
[name_m]Sebastian[/name_m] —> suh-BASH-chin
[name_m]Stefan[/name_m] —> steh-FAWN
[name_m]Xavier[/name_m] —> ZAY-vyer
[name_m]Wilder[/name_m] —> WILD-urr (like the word “wild”, not rhyming with “build”)
[name_m]Hugo[/name_m] —> hyoo-go
[name_m]Theo[/name_m] —> thee-o (“th” of “three”, not “this”)
[name_m]Lucien[/name_m] —> loo-syehn (but [name_m]Lucian[/name_m] would be loo-shin)
[name_m]Ivan[/name_m] —> eye-van