32 Sq. ft. of unencumbered floor space will house at the maximum 8 guinea fowl and nothing else. You really need at a minimum 4 sq. ft. of clear floor space for each guinea. I absolutely would not try to jam guineas and chickens into such a small area.
When it comes to guineas, 96 sq. ft. (8'x12') is not a very big space especially if you want them to peacefully share it with other poultry. That is what I have and it becomes cramped quarters for just the 10 to 12 guineas that I keep in it. I can imagine what they would do to any chickens if...