Is it forbidden to translate and publish manga stories despite changing the concepts and deleting romantic relationships from them, or because not translating them would drive readers to English versions that do not adhere to Islamic guidelines?

Reducing the religious prohibitions in translation does not entirely remove the حرمة (prohibition), because any remaining visible or audible prohibitions or misconceptions are the responsibility of the translators. It is not permissible to excuse this by claiming that a large segment of people follow these films. If translators can remove everything that violates Islamic law, then there is no blame on them; otherwise, the responsibility falls upon them.