Are you sure about the monthly basis? I mean, it's definitely possible but rushing things to keep a short deadline might not be the best of ideas.
As I said if I can get the inside of all the locations done, and the core gameplay it shouldn't take too long. Of course I do think you're right maybe monthly is a bit too much, but the voice lines and the cutscenes would take the longest period of time. So at least on my end, I might be able to get one chapter done in, at most 3 months.