Where is your proof they had audio less video only NEP?
You are really not understanding the situation with the DBZ NEPs that Umino is trying to tell you.
FUNi dubbed the NEPs for the English dub using the music and effects that were used for that dub, but did not include them in any of the DVD releases
prior to the Dragon Boxes because they were not given the Japanese audio for them by Toei. Said DVDs were dual-audio with the English dub and original Japanese, so FUNi had access to the Japanese music and effects for the episodes to create an optional third audio track that combined the Japanese music with the English dub dialogue for those who wanted to hear the Japanese score but still watch the show in English. BUT, since Toei never sent them the audio of the NEPs, they couldn't create that third audio track for the NEPs since they did not have the Japanese music for those NEPs. Thus, they were omitted from those DVD releases since, for those sets, it would not have made sense to keep the NEPs if they couldn't play the Japanese music for them if one were watching the DVDs with either of the Japanese music audio tracks.
Conversely, they DID get the Japanese video
and audio for the NEPs in the Dragon Box DVD sets, which came out YEARS later long after the DBZ English dub was done and over with. BUT, because they never got the Japanese audio for the NEPs all those years ago back when they were first dubbing and re-dubbing and re-re-dubbing DBZ out the wazoo, they never got to create that previously-described combination English dialogue/Japanese music audio track for the NEPs, they had no compatible English dub version of the NEPs to apply to the particular English dub audio track that was used for the Dragon Boxes, because said English dub audio track was the combination English dialogue/Japanese music track instead of the English dub/English music track that did feature the NEPs but which was also omitted entirely from the Dragon Boxes/
The reason the English dialogue/English music audio track was omitted from the Dragon Boxes was because the Dragon Boxes were trying to be as authentic to the viewing experience of the Japanese version as possible. The Japanese audio track is even set as the default one despite the Dragon Boxes being released in a primarily English-speaking market. And by the time the Dragon Boxes were released, FUNi was no longer dubbing the original DBZ anime, so they weren't going to create an all new English dialogue/Japanese music audio track just for the NEPs, because doing so would have been impractical from an economic standpoint. Therefore, FUNi simply used the Japanese dialogue/Japanese music audio for all audio tracks of their Dragon Box DVD sets because that's all that they had to work with for this set.
They weren't going to use the English dub versions of the NEPs since those had the dub music instead of the Japanese music, which would have been the wrong music to use for these highly Japanese-centric DVD sets. They obviously didn't want any of the dub music used in the Dragon Boxes at all since the Dragon Boxes were such special releases and that using any of the dub music would have been seen as a detriment to the authenticity of the Japanese version. So, they just left the Japanese audio intact for the NEPs in both audio tracks. Basically, the English dub audio track included in those sets is treated as little more than an extra than anything, with the Japanese audio track being the main one, unlike their older DVD releases that focused more on the English dub tracks over the Japanese one, as evidenced by
those older sets' omitting the NEPs due to their lacking the Japanese audio for them back at the time long before the Dragon Boxes were ever even a thing.
