Did FUNimation even dub the next episode preview for Dragon Ball?
Nope. Chances are FUNi may not have received them in any way, shape or form.
I didn't watch it in original Japanese broadcast form so I wasn't even aware that that they had them.
Indeed, DB had NEPs in its original broadcast just like Z, GT, and Kai.
Unless I'm mistaken the ending credits for Dragon Ball season sets only list the voice actors but not what characters they played (I hate these types of credits the most!). I know for sure that the Dragon Ball DVD singles I borrowed from my local library have these type of credits not sure about the season sets.
I think it's the same on the season sets.
And I agree, it sucks when a cast list doesn't say who plays who.