Late to the party but as someone who's spent the last few years learning different languages this was a beautiful gift. Also since Spanish names have always been the same as English ones getting to see Ferrodada (as in ferro + rodada) and Pelarena (pelo, hair + arena, sand) is kinda striking. Funny that in Italian and French Sandy Shocks' name also mentions hair, guess the English version didn't want to emphasize the same thing as in Flutter Mane.
I'm very curious what Entei's name will be, Gouging seems like the only option and in Spanish it's clearly Flama (Flamardiente has 12 characters but seems a bit repetitive, maybe another word that starts with A?), Italian is kinda hard because Val makes me think lava but not really, French is clearly Feu but German just stumps me.
For Terrakion, Iron Boulder is the clear winner although in Spanish it can't be Cascote, Piedra or Roca since they aren't between those options (obviously starting with Ferro). German is between Fa- and Ha- so it also doesn't leave many options, maybe Eisenfelsen? Which totally sounds like someone's last name. In Frenche we know it ends in "de Fer" but it can't be Roche since it'd be after Rocabot, it's possible it's just Roc.
Finally, the peach is clearly Peach in English and Spanish, Pêche in French. In Italian peach is pesca but that doesn't seem right, maybe it keeps the English name? And German has to be a pun because peach is Pfirsich, unfortunately I don't know enough to figure it out. It seems that the loyal three are puns between Italian and Japanese (Boninu is bon + inu, Benesaru is bene + saru and Beatori is beatus + tori) so it's likely some Italian word + momo.
Dunno if I got across how much fun I had thinking about this, lol.
Edit:
Wow I didn't know that, it's definitely a very cool pun then especially since it has a (somewhat) old use. Guess I have to give them more credit for their name wordplay.