About the never be Episode 3...

[nireth]

The only thing I remember reading here was that the content of Black Plague was actually supposed to be spread over two episodes, so one scenario I could imagine is that episode 2 would've focused more heavily on a longer search for Dr. Eminiss ([REQUIEM SPOILER]

Spoiler below!

His voice is quite heavily featured in Requiem, which surprised me, so perhaps some of that was actually recycled from the three episode project

[/REQUIEM SPOILER]), ending perhaps with Philip finding his father and part 3 being centred around Dr. Swanson and the Tuurngait in more detail.

That's really just a guess though, I don't even know if what I read here is actually the truth.