Well, you can edit and distribute editable MMD models, but modelers usually set additional conditions for editing and/or redistributing (and of course, trading) their models.
DO NOT EDIT AND/OR REDISTRIBUTE (and trade) MODELS UNLESS YOU HAVE THE FULL COMMAND OF JAPANESE TO READ THE ATTACHED TOS.
Full command means you can read Japanese newspapers or academic papers. Basic conversation skill is not enough. You should also refrain from distributing your translation unless you have the full command of Japanese. If you spread a grave mistranslation, you would be involved in a copyright trouble.
In addition machine translators are not reliable. Japanese language has tons of homophones, conjugations and particles. A slightest misreading leads to the total nullifying a sentence.
Here is an example.
"Be not afraid of greatness: some are born great, some achieve greatness, and some have greatness thrust upon them."