There were no pronounciation of [V] and [Di] before Meiji era I heard. Meiji government finished Isolationism and then a lot of words have been coming to Japan from overseas countries. So words of foreign origin sometimes can be spelled in 2 ways. 例）violin →ヴァイオリン、バイオリン By the way,my grandmother isn't able to say "ディ"　so she calls Disney デズニー. You can choose the spell of your Diddy in Japanese. Which　sounds is similar to Diddy do you think,デディ or ディディ or ディッディ？ Hope this help you.

V is often written "バ・ビ・ブ・ベ・ボ" Victoria ヴィクトリア　　ビクトリア both of them are OK. Diddi 　　ディディ　　　or ディッディ　　 I don't understand Diddi sounds .