I am not particularly familiar with how play by post usually works, but there seems a troubling lack of active players in the player base. Is this normal for play by post games?

It is usual that the post frequency fluctuates. Generally what happens is when a key member is posting less frequent, the whole posting continuety drops.

In this case, I believe Mercury has some challenge to keep up the posts due to being very busy with his job.

Ah. Thank you for answering that. I was a little worried that the lack of replies was indicating a lack of game interest. I'm glad to hear that it is normal for things like that to be the case.

Yeah totally normal - Fwurg is a slow cooking game ^_^