Bile Blight has only one target. Other creatures with that name are not targeted. For example, a creature with hexproof will still get -3/-3 if it has the same name as the target creature.
If the target creature is an illegal target as Bile Blight tries to resolve, it won't resolve and none of its effects will happen. No creature will get -3/-3.
Unless a token is a copy of another permanent or was explicitly given a name by the effect that created it, its name is the subtypes it was given when it was created plus the word "Token." For example, if an effect creates a 1/1 Soldier creature token, that token is named "Soldier Token."