That's their names in the Dub. Since this is an 'English Translation', GokUsama would've needed to use the names for these reasons.1. So it wouldn't confuse people about the characters. Since people in the west grew up with the dub mostly
2. It's the official English names for the Characters.
3. This is the English Patch meaning the names would be in 'English Terms'.
Hopefully, you understand my point.
Seems legit.
I think the names would be translated/adapted accord the different dubs, would be curious to see how would do the spanish translation team, there are diferences between spanish from Spain and spanish from LA.
Also: I've noted that one of the spiritualist's skills is called "Spirit bomb",and correct me if I'm wrong, but spirit bomb isn't the english equivalent for Genki-tama? I think that skill should be called "sokidan" (take a look on this video)