This is a fun way to brainstorm, but a system this size will never work exactly as you plan it, so judging it overall at this stage isn't going to do much. This will be a lot easier if you plan in chunks and adjust as you go along (as I assume you already know you'll be doing). Start with one bit at a time.

What are your favorite options here in terms of modules? If you could only start with 84hp, what would you pick?

If this is a bit and I'm missing it, I apologize.