Creator of the original Ja Wizardman 4 here. First off, yes, this is sanctioned. It's unofficial and ambiguously canon at best but done with permission. Yes, it goes Ja Wizardman 4 -> Ja Wizardman, with The Old Papers V: Stratopause somewhere in between if I ever get that project off the ground.
This thing is amazingly goodbad and I loved every moment of it. It's not perfect, and I ran into some game-breaking bugs, but for something this ambitious made that quickly that's to be expected.
Also, don't bother playing the original, it's truly awful. Even the remastered version is merely an improvement from unplayably horrendous to barely tolerable.