I like the project, the good thing is that 4 of the 4 Goemon are already translated into English and Spanish and 3 of the 4 already have their title Westernized by you.
Ganbare Goemon! - Karakuri Douchuu (Mystical Ninja)
Ganbare Goemon 2 (Japan) (Mystical Ninja 2)
Ganbare Goemon Gaiden - Kieta Ougon Kiseru (Japan) (Mystical Ninja 3 - The Missing Golden Pipe)
Ganbare Goemon Gaiden 2 - Tenka no Zaihou (Japan) (Mystical Ninja 4 - Treasures of the World)
Only the 4 would be left to put its respective western title. Is it in your plans?