Here's a layout for how things would be put down:
(DONE IN GM)
Overworld/Interiors/Dungeons are all mapped. The game is basically designed before any coding/spriting takes place.
Then, a group of programmers split up and each develop an engine. (HUD, Walking/Collision, Enemy, NPC, etc)
They ask for sprites as needed.
However, I've got a question: Should the GMD be passed from one programmer to the next with each completion of an engine, or should each developer get their own GMD and then one programmer can combine everything?
I was thinking that the game should be done in GB style (simple animations, easy coding, popular tilesets, etc) due to ease of use.
However, this can change.